Protective effects of Zhenwu decoction on kidney injury of diabetic rats induced by streptozotocin

AIM：To investigate the effects of Zhenwu decoction (ZWD) on the expression of α-smooth muscle actin (α-SMA) and NF-κB in diabetic nephropathy (DN) rats. METHODS：Diabetic rat model was induced by intrape-ritoneal injection of streptozotocin (STZ), and the animals were randomly divided into STZ group (n=22) and STZ+ZWD group (n=23). The normal rats served as control (n=16). All rats were sacrificed on 8 weeks after modeling. Biochemical assay and pathological observation (HE staining and transmission electron microscopy) were used to evaluate the effects of Zhenwu decoction on the renal function and pathological morphology. The body weight, renal index, blood glucose, total urinary protein in 24 h, and superoxide dismutase (SOD), malondialdehyde (MDA),inducible nitric oxide synthase (iNOS) were determined as well. Western blotting was used to observe the effects of Zhenwu decoction on the expression of α-SMA and NF-κB in diabetic nephropathy (DN) rats. RESULTS：Compared with normal group, the renal index, blood glucose concentration, total urinary protein in 24 h, blood urea nitrogen (BUN), serum creatinine (SCr) and MDA were significantly higher and body weight was lower in DN rats (P<0. 05). Pathological examination of the kidneys in DN group showed glomerular hypertrophy, glomerular basement membrane thickening, tubular epithelial cell degeneration, mesangial matrix proliferation, protein cast formation in some renal tubules. The protein expression levels of α-SMA and NF-κB were markedly increased (P<0.05). After ZWD treatment, the level of renal index, total urinary protein in 24 h, BUN, SCr and the expression of α-SMA and NF-κB at the protein level were significantly decreased (P<0.05). The renal histological injury in ZWD group was significantly ameliorated. CONCLUSION：Zhenwu decoction might protect kidney against STZ-induced injury via decreasing the expression of α-SMA and NF-κB.     

Effects of prostaglandin I2 on mesenteric microcirculation and property of hemorheology in rabbits with renal ischemia/reperfusion injury

AIM: To explore the effects of prostaglandin I2 (PGI2) on mesenteric microcirculation and hemorheology during renal ischemia/reperfusion (IR) injury. METHODS: 36 rabbits were randomly distributed into the sham operated group (sham group)， renal ischemia/reperfusion injury group (IR group) and PGI2+IR group（PGI2 group）. IR group received clamping for 60 min followed by 120 min of reperfusion. A microcircular microscope image analysis system was used to study the changes of mesenteric microcirculation and hemorheology at 60 min of ischemia and 120 min of reperfusion, respectively， while the blood samples were obtained for the measurement of hemorheological indexes. RESULTS: ① In IR group during the period of renal IR， the number of adhesive leukocytes and microthrombus， hemorrhage and hemorheological indexes such as blood viscosity， plasma viscosity， blood reduction viscosity， hematocrit， erythrocyte aggregation index， erythrocyte sedimentation rate， erythrocyte sedimentation rate K and plasma fibrinogen were significantly higher， while microvascular diameters， blood flow velocity and erythrocyte deformation index were significantly lower compared with sham group (P＜0.01 or P＜0.05). ② PGI2 5-40 ng·kg-1·min-1) affected the indexes of mesenteric microcirculation and hemorheology to different extent. In 10 ng·kg-1·min-1 PGI2 group， the diameters of arteriole and venule， blood flow velocity， the number of adhesive leukocytes， microthrombus， hemorrhage and hemorheological indexes significantly changed， compared with IR group (P＜0.01 or P＜0.05). Except that microvascular diameters increased remarkably （P＜0.01）， others showed no significant difference compared to sham group （P＞0.05）. CONCLUSIONS: PGI2 ameliorates the disturbance of mesenteric microcirculation and hemorheology caused by renal IR injury with the best effect at 10 ng·kg-1·min-1.     

Effect of erlotinib on renal injury in rats with STZ-induced diabetic nephropathy

AIM: To investigate the effect of epidermal growth factor receptor (EGFR) inhibitor erlotinib on kidney injury in diabetic nephropathy (DN) rat and the underlying mechanism. METHODS: The rat model of DN was induced by intraperitoneal injection of streptozotocin (STZ) at dose of 55 mg/kg. One week after STZ injection, the rats with blood glucose level exceeding 16.7 mmol/L were identified as diabetic. Diabetic rats were randomly divided into 2 groups:STZ group and STZ+erlotinib group. In addition, the normal rats were used as control group. The rats in STZ+erlotinib group were treated with erlotinib at 100 mg·kg^-1·d^-1 for 4 weeks(5th~8th week). The fasting blood glucose (FBG), serum creatinine (SCr) and 24 h urine protein were measured. The pathological changes of the kidney were observed by HE staining and Masson staining. The protein levels of EGFR, p-EGFR, transforming growth factor β1 (TGFβ1), Smad2/3, p-Smad2/3, collagen Ⅳ (ColⅣ) and fibronectin in the kidney tissues were determined by Western blot. The reactive oxygen species (ROS) level and malondialdehyde (MDA) content in the renal tissues were futher analyzed. RESULTS: Compared with control group, the levels of FBG, 24 h urine protein and Scr were significantly increased in STZ group (P<0.01). Compared with STZ group, the levels of FBG, 24 h urine protein and SCr in STZ+erlotinib group were markedly decreased (P<0.05). In additon, the glomerular structure was restored to normal, the proliferative degree of mesangial cells markedly attenuated, and the epithelial cells were in alignment in STZ+erlotinib group. Moreover, erlotinib significantly inhibited the protein levels of p-EGFR, TGFβ1, p-Smad2/3, ColⅣ and fibronectin in the kidney tissues of STZ rats. In addition, erlotinib also significantly inhibited the levels of ROS and MDA in the kidney tissues of STZ rats. CONCLUSION: Erlotinib ameliorates STZ-induced diabetic nephropathy possibly through inhibiting the activation of EGFR/TGFβ1-Smad2/3 signaling pathway in association with suppression of fibrosis and oxidative stress.     

Yunpiheluo decoction alleviates diabetic kidney injury by regulating Sirt1/AMPK signaling pathway and activating autophagy

AIM: To observe the effect on Yunpiheluo decoction (YPHL) on renal injury in type 2 diabetic rats and to explore the mechanism from the perspective of Sirt1-AMPK-autophagy. METHODS: Male Zucker diabetic fatty (ZDF) rats (n=24) were randomly divided into model group, Sirt1 over-expression group and YPHL group, and fed with high-fat and high-sugar diet for 10 weeks. ZL rats were used as normal control and fed with normal diet for 10 weeks. After 10 weeks, urine and blood were collected for renal function detection. The rats were sacrificed and specimen was submitted. In addition, the mRNA expression of Sirt1 was analyzed by real-time PCR. The protein levels of Sirt1, AMPK, p-AMPK, LC3 and P62 in the renal tissues wene determined by Western blot. The renal pathological changes were observed under light microscope with HE and Masson staining. RESULTS: Compared with control group, fasting blood glucose (FBG), urinary protein (UP), urinary albumin (U-ALB) and serum creatinine (SCr) in model group were obviously increased (P<0.01). The mRNA expression of Sirt1 was decreased (P<0.05). The protein levels of SIRT1, AMPK, p-AMPK and LC3-II/-I were decreased (P<0.01), and P62 was increased (P<0.01). Glomerular focal fibrosis, focal renal tubular epithelial cell vacuolation, necrosis, shedding and atrophy, tubular type, and renal interstitial fibrosis were observed. Compared with model group, FBG was obviously decreased in Sirt1 over-expression group (P<0.01), but it showed no significant change in YPHL group (P>0.05). SCr and U-ALB were decreased (P<0.05), Sirt1 mRNA was increased (P<0.05), the protein levels of SIRT1, AMPK, p-AMPK and LC3-II/-I were increased (P<0.01), and P62 was decreased (P<0.01) in Sirt1 over-expression group and YPHL group. HE and Masson staining showed that the renal damage in Sir1 over-expression group and YPHL group was attenuated. CONCLUSION: Yunpiheluo decoction may protect the kidney by increasing the expression level of Sirt1, activating AMPK, and regulating autophagy.     

Hypolipemic and hypoglycemic effects of total triterpenoids from Psidium guajava leaves on type 2 diabetic rats

AIM: To investigate the effects of total triterpenoids from Psidium guajava leaves (TTPGL) on blood glucose and lipids in type 2 diabetic rats. METHODS: The diabetic rats were induced by intraperitoneal injection of streptozotocin at dose of 35 mg/kg and feeding with high-fat diet. The animals were divided into 5 groups: diabetic model control group (model), TTPGL treatment groups (with the doses of 60, 120 and 240 mg/kg, respectively) and rosiglitazone treatment group (3 mg/kg). Another 12 normal SD rats were used as the normal controls. The rats received daily treatment for 6 weeks, and then the levels of fasting blood glucose (FBG), fasting insulin (FINS), triglyceride (TG), total cholesterol (TCH), free fatty acid (FFA), glycosylated hemoglobin (GHb) and glycosylated serum proteins (GSP) were measured. The protein expression of peroxisome proliferator-activated receptor γ (PPARγ) in adipose tissues was detected by Western blotting. RESULTS: Compared with normal control group, the levels of FBG, GHb and blood lipids were increased in type 2 diabetic rats. The FINS, insulin sensitivity index, and the protein expression of PPARγ in adipose tissues were decreased. Compared with model group, the levels of FBG and GSP were decreased,and the FINS, insulin sensitivity index, and the protein expression of PPARγ in adipose tissues significantly increased in TTPGL treatment groups (with the doses of 120 and 240 mg/kg). The levels of serum TG,TCH and FFA were significantly lower in TTPGL treatment groups (P<0.01 or P<0.05) as compared with the model controls. CONCLUSION: TTPGL decreases the levels of blood glucose and lipids in diabetic rats. TTPGL also increases serum insulin level and improves insulin sensitivity. The action mechanism of TTPGL may be related to the increase in the protein expression of PPARγ.     

Effect of interlukin-22 antibody on diabetic nephropathy via inhibition on Snail1 expression

AIM:To investigate the effect of interlukin-22 (IL-22) on diabetic nephropathy (DN) and its possible mechanism. METHODS:C57BL/6 mice were randomized to normal control (NC) group,DN group, DN+recombinant IL-22 (rIL-22) group and DN+IL-22 antibody (anti-IL-22) group. After successful establishment of diabetes model for 8 weeks, the mice in DN+rIL-22 group and DN+anti-IL-22 group were intraperitoneally injected with rIL-22 (200 μg/kg) and anti-IL-22 (200 μg/kg), respectively, and the mice in NC group and DN group were intraperitoneally injected with 0.1% bovine serum albumin, twice a week for 4 weeks. After the intervention, blood glucose, kidney function, 24 h urine microalbumin (m-Alb) and 24 h urine creatinine (UCr) were measured. The pathological changes of renal tissues were observed under light microscope. The mRNA expression of Snail1 was detected by qPCR. The protein levels of fibronetin (FN) and E-cadherin were determined by Western blot. RESULTS:After the intervention, the ratio of 24 h m-Alb/UCr increased significantly in other model groups compared with NC group (P<0.05). The levels of 24 h m-Alb and 24 h UCr increased significantly in DN+rIL-22 group compared with DN group (P<0.05). However, in DN+anti-IL-22 group, the levels of 24 h m-Alb, 24 h UCr and 24 h m-Alb/UCr ratio were significantly lower than those in DN group and DN+rIL-22 group (P<0.05). The tubular epithelial cell vacuolar degeneration, protein cast formation and glomerular mesangial expansion in the renal tissues from diabetic mice were observed under light microscope. The lesions were more severe in DN+rIL-22 group, but attenuated in DN+anti-IL-22 group. The mRNA expression of Snail1 increased significantly in diabetic mice (P<0.05), but decreased significantly after a 4-week intervention by anti-IL-22 (P<0.05). The expression of FN, an extracellular matrix protein, increased significantly in DN+rIL-22 group (P<0.05). The expression of E-cadherin, an epithelial-mesenchymal transition marker, decreased significantly in DN+rIL-22 group as well (P<0.05). CONCLUSION:IL-22 neutralizing antibody may attenuate microalbuminuria and delay the progression of DN via inhibition of Snail1 expression in the renal tubular epithelial cells.     

Influence of paricalcitol on renal tubulointerstitial fibrosis in diabetic nephropathy

AIM: To investigate the effect of paricalcitol (P) on renal tubulointerstitial fibrosis and the underlying mechanisms in diabetic nephropathy (DN).METHODS: DN rat model was induced by a single intraperitoneal injection of streptozotocin after fasting. The animals were randomly divided into 2 groups:the DN rats in paricalcitol-intervened group (group P) were injected intraperitoneally with paricalcitol dissolved in propylene glycol after the day when the model was induced successfully at a dose of 0.4 μg/kg (3 times a week); the DN rats in DN group (group D) were given isopyknic propylene glycol. Normal control group (group C) was also set up. The samples of blood, urine and renal tissue were collected after intervention of paricalcitol for 12 weeks. The biochemical indexes were measured. The renal tissues were used for pathologic observation and determining the expression of transforming growth factor-β1 (TGF-β1), Wnt-4, β-catenin and Klotho by immunohistochemistry and Western blotting. In addition, the correlation among the above indexes was analyzed.RESULTS: (1) Scr, BUN and 24 h urine protein increased significantly in group D compared with group C, while decreased in group P compared with group D (P<0.05). (2) The area of renal tubulointerstitial fibrosis increased in group D compared with group C, while decreased in group P compared with group D (P<0.05). (3) The expression of Klotho decreased, while the expression of TGF-β1, Wnt-4 and β-catenin increased in group D compared with group C (P<0.05). Compared with group D, the expression of Klotho increased, while the expression of TGF-β1, Wnt-4 and β-catenin decreased in group P (P<0.05). (4) The expression of Klotho was negatively correlated with the fibrosis area, TGF-β1, Wnt-4 and β-catenin (P<0.05).CONCLUSION: Paricalcitol inhibits renal tubulointerstitial fibrosis in DN by promoting the expression of renal Klotho, and inhibiting Wnt/β-catenin signaling pathway activation and TGF-β1 synthesis.     

Protective effects of luteolin on STZ-induced diabetic kidneys

AIM: To explore the protective effects of luteolin on the diabetic kidneys. METHODS: Male Sprague-Dawley rats were randomly divided into 5 groups: normal control group, diabetic model group and the groups of diabetic rats treated with luteolin at a low dose, a middle dose and a high dose. The diabetic model was induced by a single intraperitoneal injection of streptozotocin (STZ,65 mg/kg). Blood glucose, urine protein, the activity of superoxide dismutase and catalase in serum and kidney, and the content of malonaldehyde(MDA) in kidney were analyzed by biochemical methods. Western blotting was used to detect the protein expression of transforming growth factor-β₁(TGF-β₁) and plasminogen activator inhibitor-1(PAI-1) in the renal cortex. The morphological changes of the renal tissues were observed under microscope. RESULTS: Compared with diabetic model group, luteolin significantly reduced the level of blood glucose (P<0.01), the content of urine protein (P<0.01) and MDA (P<0.01) in the kidneys, and increased the activity of superoxide dismutase and catalase (P<0.01) in serum and kidneys in the diabetic rats. The protein levels of TGF-β₁ and PAI-1 in the renal cortex were dramatically decreased as the rats were treated with luteolin. CONCLUSION: Luteolin may exert an important protective effect on diabetic kidneys by relieving oxidative stress and inhibiting the protein expression of TGF-β₁ and PAI-1 in the renal tissues of STZ-induced diabetic rats.     

RTN1A induces renal tubular epithelial cells to secrete VEGF and IL-8 and promotes diabetic nephropathy renal fibrosis via ERK signaling pathway

AIM:To investigate the effects of reticulon 1A (RTN1A) on the secretion of vascular endothelial growth facter (VEGF) and interleukin-8 (IL-8) in renal tubular epithelial cells, and on the diabetic nephropathy (DN) renal fibrosis, and to explore the underlying mechanism. METHODS:The mouse model of DN was established, and the blood glucose, kidney index, urine microalbumin (UMA) and creatinine clearance (CCr) were measured. The protein levels of RTN1A, p-ERK, ERK, VEGF, IL-8 and renal fibrosis markers α-smooth muscle actin (α-SMA) and fibronectin (FN) were determined by Western blot. Human renal tubular epithelial cell line HK-2 was treated with high glucose, and the ERK signaling proteins, fibrosis markers and secretion of cytokines were detected by Western blot and ELISA. The cells were treated with high glucose combined with RTN1A silencing or ERK inhibitor PD98059 for 24 h, and the ERK signaling proteins, fibrosis markers and secretion of cytokines were also detected by Western blot and ELISA. RESULTS:The blood glucose, kidney index, UMA and CCr in the DN mice were significantly higher than those in control group (P<0.05), suggesting that DN model was successfully constructed. The protein levels of RTN1A and its downstream protein p-ERK, the cytokines VEGF and IL-8, and the fibrosis markers α-SMA and FN were significantly increased in the DN model mice (P<0.05). The protein levels of RTN1A, p-ERK, VEGF, IL-8, α-SMA and FN were also significantly increased in the HK-2 cells after treated with high glucose for 24 h, while these proteins were significantly decreased after silencing of RTN1A expression. CONCLUSION:RTN1A may be associated with the occurrence and development of DN. Silencing of RTN1A expression inhibits DN renal inflammation and fibrosis through ERK signaling. RTN1A may be an effective therapeutic target.     

Effects of puerarin combined with saxagliptin on renal fibrosis in type 2 diabetic rats

AIM：To observe the effects of puerarin combined with saxagliptin on renal fibrosis in type 2 diabetic rats. METHODS：Fifty male Wistar rats were used, of which 8 rats were randomly chosen as normal control group, and the remaining rats were used to establish the type 2 diabetic model. The rats that met the criterion for the diabetic mo-del were randomly divided into model group, puerarin treatment group, saxagliptin treatment group, puerarin combined with saxagliptin treatment group and metformin combined with saxagliptin treatment group. The above-mentioned drugs were administered for 8 weeks. After that period, all rats were sacrificed. The kidney index (kidney weight/body weight),and blood glucose and HbA1c were examined in all the rats. The morphological changes were observed by HE and Masson staining. The levels of TNF-α and macrophage migration inhibitory factor (MIF) in the serum were measured by ELISA. The mRNA expression of TNF-α, MIF and CD68 was examined by RT-PCR. RESULTS：Compared with normal group, the kidney index, blood glucose and HbA1c, the levels of TNF-α and MIF in the serum and the mRNA expression of TNF-α, MIF and CD68 were increased (P<0.05) in the kidney tissues of model group. Compared with model group, the kidney index, blood glucose and HbA1c, the levels of MIF and TNF-α in the serum and the mRNA expression of TNF-α, MIF and CD68 were decreased (P<0.05) in puerarin combined with saxagliptin treatment group. CONCLUSION：Puerarin combined with saxagliptin reduces blood glucose, decreases MIF and TNF-α, and down-regulates the mRNA expression of TNF-α, MIF and CD68 in the kidney tissues of type 2 diabetic rats, which may contribute to the inhibition of renal fibrosis.     

Dynamic expression of S-adenosyl-L-homocysteine hydrolase under intervention of fimasartan in early stage of type 2 diabetic cardiomyopathy rats

AIM: To detect the changes of S-adenosyl-L-homocysteine hydrolase (SAHH) signaling pathway and related proteins under the intervention of fimasartan (FIM) in rats with diabetes mellitus (DM), and to explore the pathological mechanism of the occurrence and development of diabetic cardiomyopathy (DCM). METHODS: The type 2 diabetic rat model was established by injection of streptozocin after 5-week high-fat diet. The rats were randomly divided into control group, DM group, and DM+FIM group. Fasting blood glucose (FBG), total cholesterol (TC), triglyceride (TG), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C) and fasting insulin (FINS) levels were tested. M-mode echocardiography was performed for determining the heart functions. High-performance liquid chromatography (HPLC) was used to detect homocysteine (Hcy), S-adenosylmethionine (SAM) and S-adenosyl-L-homocysteine (SAH). The alteration of SAHH in myocardium was determined by Western blot. RESULTS: The success rate of type 2 diabetic rat modeling was 84%. Compared with DM group, the body weight of the rats in DM+FIM group increased significantly (P<0.05), while cardiac index, left ventricular index, FBG and LDL-C were significantly reduced (P<0.05). The results of echocardiography showed that ejection fraction increased (P<0.05) in DM+FIM group. HPLC detection showed that the level of Hcy and the ratio of SAM/SAH were significantly reduced (P<0.05). The results of Western blot showed that the expression of SAHH in DM group was increased compared with control group, while that in DM+FIM group declined (P<0.01). CONCLUSION: The expression of SAHH, Hcy and other related factors may be important during the occurrence and development of early DCM, and FIM may play a role in this process as an inhibitor of SAHH.     

Protective effects of riboflavin on diabetic nephropathy in STZ-induced diabetic rats

AIM: To explore the protective effects of riboflavin on the kidney in streptozotocin (STZ)-induced diabetic rats. METHODS: Male Sprague-Dawley rats were randomly divided into 3 groups: normal control group, diabetic model group and riboflavin-treated group. Diabetes was induced by a single injection of STZ (dissolved in 0.01 mol/L citrate buffer, pH 4.5, 65 mg/kg, ip) in rats. The biochemical methods were used to measure the contents of urine protein and malondialdehyde in the kidney, and the activities of superoxide dismutase (SOD) and catalase (CAT) in serum and renal tissues. Furthermore, the protein expression of TGF-β1 and plasminogen activator inhibitor-1(PAI-1) in renal cortex was detected by Western blotting. The morphological changes of renal tissue were observed under microscope.RESULTS: Compared to the diabetic model group, riboflavin significantly increased the activities of SOD and CAT (P<0.01) in the serum and renal tissues, and decreased the contents of urine protein and MDA (P<0.01) in the renal tissues in riboflavin-treated group. The levels of TGF-β1 and PAI-1 in the renal cortex were dramatically decreased in the treated diabetic rats compared to the diabetic model rats (P<0.01).CONCLUSION: Riboflavin inhibits the protein expression of TGF-β1 and PAI-1 in renal tissue of STZ-induced diabetic rats. Riboflavin may alleviate the pathologic changes and play an important protective role in diabetic kidneys.     

Influence of Tangshenfang on diabetic liver injury and the expression of SIRT1 and PGC-1α in the liver tissue

AIM: To observe the effect of Tangshenfang (TS) on the liver protection and the levels of silent information regulator 1 (SIRT1) and peroxisom proliferator-activated receptor γ coactivator-1α (PGC-1α) in the liver tissue. METHODS: The rat model of diabetes mellitus (DM) was established by intravenous injection of streptozotocin (STZ;30 mg/kg) after having the high fat/high glucose diets for 1 month. The diabetic rats were randomly divided into DM group, DM with high-dose TS (TS^Hi) group, medium-dose TS (TS^Med) group and low-dose TS (TS^Low)group. The normal rats were served as control group. There were 8 rats in each group. After treatment with TS for 12 weeks, the serum biochemical indices including fasting blood glucose (FBG), triglyceride (TG), alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were tested. Fasting insulin (FINS) was also detected by radioimmunoassay, and homeostatic model assessment for insulin resistance (HOMA-IR) was calculated. The serum levels of tumor necrosis factor-α (TNF-α) and interleukin-1 (IL-1) were measured by ELISA. The activity of SOD and content of MDA in the liver tissues were measured by the methods of hydroxylamine and thiobarbituric acid. The liver pathological changes were observed under light microscope with HE and Masson staining. The protein expression of SIRT1and PGC-1α in the liver tissues was determined by Western blot. RESULTS: In DM group, serum FBG, TG, ALT, AST, FINS, HOMA-IR, TNF-α and IL-1 were obviously increased compared with the control group (P<0.01). The fatty changes, local necrosis, inflammation and fibrosis in the liver tissues were observed. The content of MDA in liver increased, while the activity of SOD decreased markedly. The protein expression of SIRT1 and PGC-1α was decreased (P<0.05). In TS treatment groups, all these changes in DM rats were markedly reversed by TS, and the protein expression of SIRT1 and PGC-1α in the liver tissues was markedly increased. CONCLUSION: TS may protect the rats from diabetic liver injury by increasing the expression of SIRT1 and PGC-1α, and thereby improving insulin resistance and oxidative stress.     

Effect of resveratrol on autophagy and renal interstitial fibrosis in kidney of diabetic mice

AIMTo observe the effect of resveratrol (Res) on renal autophagy level and renal interstitial fibrosis in the mice with diabetes mellitus (DM), and to discuss the possible mechanism. METHODSThe wild-type C57BL/6 mice were randomly divided into 3 groups, including normal control (NC) group, DM group and Res group (8 in each group). The diabetic mouse model was established by injection of streptozotocin. After 8 weeks of successful replication of the diabetic model, Res was given to the mice in Res group by continuous gavage for 12 weeks, and then the mice in each group were sacrificed to detect the relevant biochemical parameters. The pathological changes of the kidney tissues were observed by HE staining and Masson staining. The levels of the proteins related to autophagy, epithelial-mesenchymal transition (EMT) and fibrosis were determined by Western blot. The mRNA expression of collagen type IV (Col IV), α-smooth muscle actin (α-SMA) and E-cadherin were detected by real-time PCR. RESULTSCompared with NC group, fasting blood glucose (FBG), kidney index (KI), serum creatinine, 24-hour urinary albumin excretion rate and 24-hour urine total protein were remarkably increased in DM group (P<0.05). The results of HE and Masson staining indicated that renal tissue presented fibrosis in DM group. The protein levels of E-cadherin, beclin-1, microtubule-associated protein 1 light chain 3-II (LC3-II) were reduced in DM group, while the levels of α-SMA, Col IV and Snail1 were increased (P<0.05). After intervention with Res for 12 weeks, all the relevant biochemical parameters and KI were reduced (P<0.05) except FBG (P>0.05), and renal fibrosis lesions were obviously alleviated. Compared with DM group, the protein levels of E-cadherin, beclin-1 and LC3-II were increased in Res group, but the protein expression levels of α-SMA, Col IV, Snail1 were reduced (P<0.05). Compared with DM group, the mRNA level of E-cadherin was increased in Res group , but the mRNA levels of Col IV and α-SMA were reduced (P<0.05). CONCLUSION Resveratrol significantly inhibits EMT and reduces renal interstitial fibrosis in diabetic mice, and its mechanism may be related to the promotion of renal autophagy.     

Effects of hypoxia exposure for different time on structure and function of red blood cells in rats

AIM: To investigate the effects of hypoxia exposure on the structure and function of erythrocytes in rats at different time. METHODS: Male SD rats (n=40) were randomly divided into 5 groups, normal control group, 1-week hypoxia group, 2-week hypoxia group, 3-week hypoxia group and 4-week hypoxia group, with 8 rats per group. The rats in hypoxia groups were placed in the simulated 5 800 m of high altitude in a hypobaric chamber for different time. The values of detected blood, erythrocyte deformation index, erythrocyte osmotic fragility, erythrocyte oxygen dissociation, erythrocyte apoptosis and bone marrow biopsy were determined. RESULTS: Compared with normal control group, the red blood cell count, hemoglobin content, mean corpuscular volume and mean corpuscular hemoglobin significantly increased (P<0.01). Eversion rate of phosphatidylserine of erythrocytes increased. Oxygen half-saturation of hemoglobin increased (P<0.05). Bone marrow erythroid proliferation increased. The erythrocyte deformation index and erythrocyte osmotic fragility decreased significantly (P<0.01). In addition, oxygen dissociation curves shifted to the right. CONCLUSION: In the early stage of hypoxia, compared with normal control group, the changes of erythrocyte structure and function increase the oxygen supply to the tissue and are conducive to adapting to the plateau. However, with the extension of hypoxia, excessive erythrocytosis results in thrombosis, microcirculation disturbance and aggravating tissue hypoxia.     

Expression of zinc-finger transcription factor Snail 1 in the kidney of diabetic rats

AIM: To explore the expression of Snail 1 in renal tissues of diabetic rats, and to investigate its contribution to the progression of diabetic nephropathy. METHODS: Streptozotocin-induced diabetic rats were randomly divided into 2, 4, 8, 12, 16, 20, 24 weeks groups and 16 week A, 20 week A and 24 week A groups. A groups were treated with insulin to control blood glucose to normal level from the 13th week. Control groups were set up in age-matched time points. Blood glucose, 24 h urine protein, serum creatinine (Scr) and kidney index of rats were measured. Periodic acid-silver (PAS) staining was used to observe the renal pathological changes. The mRNA and protein expressions of Snail 1 and FN in renal cortex were detected by RT-PCR and immunohistochemical staining, respectively. Western blotting was employed to detect the expression of Snail 1 protein in the renal cortex. RESULTS: The levels of blood glucose, Scr, kidney weight index were increased remarkably in diabetic rats as compared with those in control groups (P<0.05, P<0.01), and decreased remarkably in the insulin-treated rats as compared with those in the diabetic rats (P<0.05, P<0.01). The Snail 1 protein was not detected by immunohistochemical staining in normal renal tissues. However, strongly positive staining was observed in renal tubules of diabetic rats. A time-dependent loss of Snail 1 expression was detected in the kidney in insulin-treated rats. The Snail 1 protein and mRNA of Snail 1 and FN were significantly up-regulated in the diabetic rats as compared with those in controls (P<0.01), while down-regulated in the insulin-treated diabetic rats (P<0.01). A close positive relationship existed between the mRNA expression of Snail 1 and FN (r=0.800, P<0.01). The level of Snail 1 protein expression was positively correlated with blood glucose, urine protein, Scr, kidney index (r=0.877, 0.694, 0.522, 0.875, P<0.01).CONCLUSION: These findings suggest that Snail 1 gene and protein expression are up-regulated in the kidney of rats with diabetes and may be involved in the pathogenesis of diabetic nephropathy.     

Effect of astragalus polysaccharin on expression of nephrin and podocin in podocytes of early diabetic nephropathy rats

AIM: To observe the effects of astragalus polysaccharin (APS) on the expression of nephrin and podocin in podocytes of diabetic nephropathy (DN) rats.METHODS: The rat model of diabetes was induced by intraperitoneal injection of streptozotocin (STZ).The diabetic rats were randomly divided into 2 groups by the treatment without or with APS: STZ group (n=8) and STZ+APS group (n=8).In addition, 8 non-treated rats served as control.All the rats were treated with APS or normal saline orally by gavage for 8 weeks.The concentration of blood glucose was monitored on week 2, 5 and 8 after treatment.Eight weeks later, the body weight and renal index were measured.Total urine protein in 24 h, blood urea nitrogen (BUN) and serum creatinine (SCr) were detected by biochemical methods.The pathological changes of the kidneys were also observed under light microscope.The protein levels of nephrin and podocin in the kidney tissues were also determined by Western blotting.RESULTS: After APS intervention, the levels of renal index, blood glucose concentration, 24-hour total urine protein, BUN and SCr were significantly lower and body weight was higher than those in STZ group (P<0.05).The renal pathological status in APS group was significantly improved and the expression levels of nephrin and podocin also markedly increased (P<0.05).CONCLUSION: APS might protect kidney against STZ-induced injury via increasing the expression of nephrin and podocin in podocytes.     

Effect of irbesartan on nephrin expression in the podocyte of early diabetic nephropathy rats

AIM: To investigate the expression of the nephrin in podocyte of the diabetic nephropathy(DN) rats and the mechanism of irbesartan-induced renal protection.METHODS: The DN model was established by a single injection of streptozotocin(STZ),and DN rats were randomly divided into 2 groups: model group and irbesartan treatment group.In addition,the normal rats served as a normal control group. All the rats were received daily gavage respectively for 8 weeks. The urinary protein quality in 24 hours,body weight(BW),kidney weight (KW),KW/BW,glucemia,urea nitrogen,creatinine,total cholesterol, triacylglycerol were detected with correlative methods and the pathological changes of kidney were also detected with optic microscope and transmission electron microscope.The expression of nephrin in podocyte were detected by immunohistochemistry. RESULTS: In DN rats, irbesartan reduced the urinary protein quality in 24 hours (P<0.01) and alleviated the damage of kidney. Meanwhile，the expression of nephrin was declined remarkably in podocytes in irbesartan treatment group compared with model group（P<0.05）.CONCLUSION: Irbesartan might protect kidney against STZ-induced injury via decreasing the expression of nephrin in podocytes.     

Expression of CTGF and its role in the streptozotocin-induced diabetic rat kidney

AIM:To investigate the change of connective tissue growth factor(CTGF) expression and its role in streptozotocin-induced diabetic rat kidney. METHODS:Male SD rats were randomly divided into two groups: control(sham operated rats, group C，n=32) and diabetic rats (group DN，n=35). Rats in each group were sacrificed at 1, 2, 4, and 8 weeks respectively after induction of diabetes. Body weight（BW）, blood glucose（BG）, 24-hour urine volumn（UV）, kidney weight, KW/BW,24-hour urinary albumin excretion (24Ualb), creatinine clearance (Ccr), kidney weight (KW), KW/BW, glomerular area (A_G), proximal tubular area (A_T) and the width of GBM、TBM at each time point were measured. Expression of CTGF and α-SMA were detected by immunostaining. RESULTS:There was a significant increase of 24 h Ualb, Ccr, KW/BW, A_G, V_G and the expression of CTGF in glomeruli and tubuli from week 1 onward in diabetic rats compared with those in group C (P<0.05, P<0.01, respectively), and an increasing expression of α-SMA mainly located in dilated tubuli from week 4 was found in group DN, which was more evident at week 8 accompanied by the decrease in A_T. Diabetic rats also had a significant increase in A_T from week 1 onward, which peaked at week 4. CONCLUSION:In the early stage of DN, the time-dependently upregulated CTGF might mediate the renal hypertrophy, which might be associated with the subsequent tubular epithelial-mesenchymal transdifferentiation (EMT) and renal fibrosis.     

Effects of AT1 receptor autoantibody on renal cell apoptosis and JNK expression in diabetic nephropathy rats

AIM:To study the effects of angiotensin Ⅱ type 1 receptor autoantibody (AT1-AA) on the apoptosis of renal cell and the expression of c-Jun N-terminal kinase (JNK) in diabetic nephropathy (DN) rats. METHODS:High-sucrose and high-fat diet and intraperitoneal injection of streptozotocin were utilized to induce DN rat model. We employed enzyme-linked immunosorbent assay (ELISA) for serum AT1-AA and TUNEL staining for renal cell apoptosis. Furthermore, Western blotting was performed to measure the levels of endoplasmic reticulum stress (ERS) chaperone glucose-regulated protein 78 (GRP78) and ERS-associated apoptosis protein p-JNK. RESULTS:The renal cell apoptotic rate in DN group was significantly increased compared with NC group, and the apoptotic renal cells in AT1-AA positive DN rats were much greater than those in AT1-AA negative DN rats (P<0.05). The protein levels of GRP78 and p-JNK were significantly increased compared with NC group. GRP78 and p-JNK protein levels also significantly increased in AT1-AA positive DN rats compared with AT1-AA negative DN rats. CONCLUSION: AT1-AA activates ERS response and induces renal cell apoptosis via the JNK apoptotic pathway in the renal tissues of DN rats.