Expression and role of SnoN in kidney tissue of diabetic rats

AIM: To observe the changes of SnoN expression in renal tissues of diabetic rats, and to elucidate the role of co-repressor SnoN protein in the diabetic nephropathy. METHODS: Diabetic nephropathy was induced by intravenous injection of streptozotocin in male Sprague-Dawley rats. The model animals were divided into 2 weeks, 4 weeks and 8 weeks groups randomly. Meanwhile other 3 age-matched normal control groups were set up. The expressions of SnoN, TGF-β₁, Smad2/3, APC were detected by immunohistochemistry staining. The SnoN proteins in renal cortex were detected by Western blotting. Blood glucose, serum creatinine and 24 h urine protein were examined by biochemistry methods. The renal morphology was checked on PAS staining sections under light microscopy. RESULTS: The results of immunohistochemistry and Western blotting showed that the expression of SnoN in diabetic renal tissues at 2 weeks was the same as the normal kidney. There was a significant decrease in DM 4 weeks (P<0.01). A time dependent increases in TGF-β₁, Smad2/3 and APC were detected in the kidney of diabetic mellitus rats. The degree of SnoN down-regulation had close relation with the increases in TGF-β₁, Smad2/3 and APC. CONCLUSION: These results suggest that in the DM, renal increase in TGF-β₁ expression may down-regulate the SnoN expression through APC dependent degradation, indicating a key role in the mechanism of diabetic nephropathy.     

Expression of SREBP-1 and SREBP-2 in kidney of type 1 diabetic rats

AIM:To investigate the expression of sterol regulatory element binding protein-1 (SREBP-1) and sterol regulatory element binding protein-2 (SREBP-2) in the kidney of type 1 diabetic rats.METHODS:The triglyceride (TG) and cholesterol content in the kidney of experimental rats were measured by the assay kits and oil red O staining.Furthermore, the expressions of SREBP-1 and SREBP-2 protein were detected by the methods of Western blotting and immunohistochemistry.The analysis of SREBP-1 mRNA was performed by in situ hybridization.RESULTS:Renal triglyceride content was markedly higher in diabetic rats than that in normal rats and the result of oil red O showed that lipid deposited in the renal tubular epithelium.Immunohistochemistry and Western blotting presented similar results that SREBP-1 protein was up-regulated in renal tubular epithelium in diabetic rats.On the other hand, SREBP-2 protein didnt show difference between diabetic rats and normal control rats.In situ hybridization confirmed the increasing of SREBP-1 mRNA in renal tubular epithelium in diabetic rats.CONCLUSION:Above results suggest that altered SREBP-1 may play an important role in the pathogenesis of renal lipid accumulation in type 1 diabetic rats.     

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.     

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.     

Effects of enalapril on inflammation in kidney of diabetic rats and its possible mechanism

AIM: To investigate the effects and mechanism of enalapril on nephritis of diabetic mice. METHODS: Diabetes was induced by injection of streptozotocin after uninephrectomy. Rats were randomly divided into three groups: control, diabetes, diabetes treated with enalapril (10 mg·kg-1·d-1 by gavage). 8 weeks after STZ injection, urine albumin excretion rate (AER) were measured, and glomerular morphology were observed by light microscopy. The levels of malonyldialdehyde (MDA) in renal tissue and urine as well as activities of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-PX) in renal tissue were determined. Immunohistochemistry for ED-1 (macrophage marker), monocyte chemoattractant protein-1 (MCP-1) and intercellular adhesion molecule-1 (ICAM-1) were performed by streptavidin-biotin complex (SABC) technique. RESULTS: Increased kidney weight, ratio of kidney weight to body weight, AER and expansion of mesangial as well as tuft areas on histological examination of the kidney were significantly attenuated by the treatment of enalapril (P<0.05, P<0.01). Elevated MDA levels in renal tissue and urine as well as decreased SOD, CAT, GSH-PX activities in renal tissue were also remitted by enalapril (P<0.05). Increased glomerular macrophage recruitment and expression of MCP-1 was significantly inhibited by enalapril (P<0.05). However, elevated ICAM-1 expression was not reduced by enalapril in glomerulus in diabetic rats. CONCLUSION: Possible mechanism of renal protection of enalapril may be at least partly related with suppression of inflammation in kidney of diabetic rats.     

Expression of TGF-β1 and Smad2/3 in kidney of STZ-induced diabetic nephropathy rats

AIM: To study the role of TGF-β/Smad pathway in the development of renal fibrosis in diabetic nephropathy.METHODS: Rats were induced to diabetic nephropathy by using tail intravenous injection of STZ.The expression of TGF-β₁, Smad2/3 protein and mRNA in kidney were examined at 2, 4, 8 and 16 weeks after STZ induction.CTGF, collagen-Ⅲ, PAI-1 mRNA expression in kidney at 16 weeks of STZ-induced diabetic nephropathy and normal rats were studied by RT-PCR.RESULTS: Weak TGF-β₁, Smad2/3 protein were detected in normal renal tissues while strong TGF-β₁, Smad2/3 staining were observed in renal tissues of diabetic nephropathy (0.057±0.030/0.223±0.040;0.017±0.010/0.153±0.010, respectively, P<0.05).The TGF-β₁, Smad2/3 protein expression were constantly high with the development of diabetic nephropathy and fibrosis (0.153±0.010, 0.122±0.050, 0.141±0.070 and 0.216±0.030 for 2, 4, 8 and 16 weeks, respectively).The TGF-β₁, Smad2 mRNA expression also increased with the development of diabetic nephropathy (2.86, 3.25 fold compared to control, respectively).The expression of TGF-β₁, Smad2, CTGF, collagen-Ⅲ and PAI-1 mRNA were significantly higher in kidney of 16 week diabetic nephropathy rats than that in normal ones (3.92, 2.95, 1.57, 1.95 and 1.97 folds compare to control, respectively, P<0.05).CONCLUSION: The results indicate that TGF-β₁/ Smad2 pathway activity might play an important role in pathophysiological process of diabetic nephropathy.It may be involved in diabetic renal fibrosis through up-regulation of CTGF and PAI-1 to promote extracellular matrix deposition.     

Expression of cathepsin B and cystatin C and its potential role in diabetic rats

AIM: To observe the expressions of cathepsin B (CB) and cystatin C (CC) in different stage of diabetic rats and to investigates their potential roles.METHODS: Sixty rats were divided into diabetes mellitus group induced by intravenous injection of streptozotocin (55 mg/kg) and normal group injected with citrate buffer. Ten rats were sacrificed respectively at the end of fourth week, eighth week and sixteenth week in both groups. 24 h urine excretion was collected in rats before sacrifice. The blood and the kidney were also collected. The mRNA and protein expressions of CB and CC in kidney were detected by real time PCR and immunohistochemical staining, respectively.RESULTS: At the end of eighth week, the expression of Ccr, 24 h urinary protein excretion, CB, CC in diabetic rats increased significantly, compared to the results at the fourth week (P<0.01 or P<0.05). With the aggravation of diabetic nephropathy, the expressions of CC, colⅣ, FN and 24 h urinary protein excretion were up-regulated significantly (P<0.01 or P<0.05). The expression of CB in diabetic rats was up-regulated at eighth week significantly (P<0.01), whereas, at the end of sixteenth week it was down-regulated significantly (P<0.01). The 24 h urinary protein excretion, the expressions of colⅣ at protein and mRNA levels and FN were negatively correlated with CB (P<0.01).CONCLUSION: The unbalance of CB and CC exists in diabetic nephropathy renal tissue, which is likely to lead to the accumulation of extracellular matrix.     

Expression and significance of thrombospondin-1 in myocardium of type 2 diabetic cardiomyopathy rats

AIM: To investigate the expression and significance of thrombospondin-1 (TSP-1) in left ventricular myocardium of type 2 diabetic cardiomyopathy (DCM).METHODS: The rat model of DCM was established by eating a high-fat diet together with injection of low dose streptozocin (30 mg/kg) intrapertoneally.After 12 weeks,the content of collagen was quantified by Masson staining.The mRNA level of TSP-1 was determined by quantification real-time RT-PCR,while the protein level of TSP-1 was analyzed by Western blotting and immunohistochemistry.RESULTS: Compared with the control group,the content of collagen in the DCM group was increased greatly (11.01±3.05 vs 16.92±3.18,P<0.01).The mRNA and protein expressions of TSP-1 were significantly higher than those in control group (0.0089±0.0034 vs 0.0141±0.0037,P<0.05；96.38±16.80 vs 129.98±16.96,P<0.05).In DCM group,the mRNA and protein expressions of TSP-1 showed significantly positive correlations with the levels of fasting blood glucose and collagen (r=0.762,P<0.01; r=0.717,P<0.05; r=0.735,P<0.01; r=0.750,P<0.01).There was a significantly positive correlation of TSP-1 mRNA level with LVEDP (r=0.658,P<0.05).In contrast,there was a significantly negative correlation of TSP-1 protein with LVSP and -dp/dtmax (r=-0.605,P<0.05; r=-0.694,P<0.05).There was a significantly positive correlation of TSP-1 protein with LVEDP (r=0.716,P<0.05).There was a significantly negative correlation of TSP-1 protein with LVSP and -dp/dtmax (r=-0.633,P<0.05; r=-0.669,P<0.05).CONCLUSION: The increased expression of TSP-1 may play an important role in the development of myocardial interstitial fibrosis in DCM.     

Expression of angiogenic factors in myocardial tissue of diabetic rats

AIM：To observe the expression of angiogenesis factors in the myocardial tissue of streptozotocin-induced diabetic rats. METHODS：The diabetic rat model was induced by intraperitoneal injection of streptozotocin. After 12 weeks, the cardiac function was measured by MPA cardiac function analysis system. The myocardial collagen volume fraction (CVF) was assessed by Masson staining. The capillary vessels was quantified as the ratio of capillary to myocyte (C/M) using CD31 immunostaining. The expression levels of vascular endothelial growth factor (VEGF), angiopoietin (Ang)-1, endostatin and Ang-2 were observed by Western blotting. RESULTS：Compared with normal control group, the left ventricular end-diastolic pressure (LVEDP) was evidently increased (P<0.01), but left ventricular pressure rise maximum rate (+dp／dtmax), left ventricular pressure decrease maximum rate (-dp／dtmax) and the ratio of capillary/myocyte (C/M) were significantly decreased (P<0.05). The CVF and the expression level of endostatin were significantly increased, whereas the expression levels of VEGF and Ang-1 evidently decreased (both P<0.05) in diabetic rats. However, no marked difference in the expression of Ang-2 between the 2 groups was observed (P>0.05). CONCLUSION：Imbalances between the angiogenic factors (VEGF and Ang-1) and anti-angiogenic factors (endostatin) may play an important role in the pathogenesis of diabetic cardiomyopathy.     

Expression of alpha-smooth muscle actin in scar tissue and its relationship with apoptosis

AIM: To examine the expression of alpha-smooth muscle actin in scar tissue, and observe the phenomenon of apoptosis and its involvement in the process of pathological scarring and the presence of myofibroblasts or absence of cell in the dermis. To investigate the potential role of reparative cell apoptosis in hyperplastic scar formation. METHODS: The samples of scar were obtained from post-burn patients undergoing plastic operation in our burn unit recently, and the samples of control came from skin donor site of the same patient correspondingly. TUNEL assays were performed to evaluate the number of apoptotic cells in scar versus normal skin. In situ hybridization and immunohistochemistry staining technique were employed to determine the expression of different dermis cells markers in scar tissue and normal skin. RESULTS: There existed evident difference in apoptotic cells in the dermis between scars tissue and normal human skin. The expression positive cells were much more in hyperplastic scars than that in normal human skin; the apoptotic cells of proliferative stage were slight more than that of mature stage. However, in proliferative stage, the number of apoptotic cells was higher for the combination of hyperplastic scar than normally healed flat scars. But in mature stage, no obviously difference was detected between hyperplastic scar and normally healed flat scar. The monoclonal anti-α smooth muscle actin (ASMA) expression was significantly stronger in proliferative stage than that of mature stage. CONCLUSIONS: With reconstitution of dermal tissue, myofibroblasts containing alpha-SM actin disappear under normal wound healing, probably as a result of apoptosis. The myofibroblast play a critical role in wound closure and in the pathologic sequelae of healing.     

Dynamic relationship between macrophage and extra cellular matrix in the kidney of rats with experimental nephritis

AIM: To observe the changes in infiltrating macrophages (Mф)and extracellular matrix (ECM) in the kidney in the progressive course of nephrotoxic nephritis (NTN). METHODS: NTN model was established with rabbit-anti-rat nephrotoxic serum. On day 3, 7, 15, 30 and 90, renal biopsies were performed. Renal histology was checked under light microscopy with HE and Masson's trichrome staining sections. Mф, fibronectin (FN), type Ⅲ and Ⅳ collagen were examined with immunohistochemistry ABC method. RESULTS: Infiltration of Mф appeared on day 3 of NTN and preceded changes of FN and collagen. On day 15 of NTN, all nephritic animals had significant proteinuria, increased serum creatinine, infiltration of Mф and deposit of entracellular matrix. On day 90 of NTN, seven nephritic animals improved significantly, while other five developed renal scarring with diffuse infiltration of Mф which positively paralleled to renal function and deposit of FN, type Ⅲ and Ⅳ collagen. CONCLUSION: Mф infiltrating into renal tissue enhances deposit of ECM and therefore plays important roles in progression or improvement of NTN.     

Expression and significance of stanniocalcin 2 in diabetic retinopathy

AIM To investigate the expression level of stanniocalcin 2 (STC2) in vitreous tissues of rats with diabetic retinopathy (DR), and to explore the relationship between STC2 and vascular endothelial growth factor (VEGF). METHODS Wistar rats were randomly divided into control group and DR group. The DR model was constructed by injection of streptozotocin. RT-qPCR, Western blot and ELISA were used to detect the expression levels of STC2 and VEGF in rat vitreous tissues. Rat retinal ganglion cells were treated with VEGFA, and the expression of STC2 was detected by RT-qPCR, Western blot and ELISA. The retinal ganglion cells were also treated with STC2 protein, and then the expression of VEGF was detected by RT-qPCR, Western blot and ELISA. Co-immunoprecipitation was used to detect the interaction between VEGF and STC2. RESULTS Compared with control group, the mRNA and protein levels of STC2 were significantly increased in vitreous tissues of the rats with DR, and the expression level of VEGF was also significantly increased in DR group (P<0.01). The expression level of STC2 was positively correlated with VEGF expression. VEGF induced the expression of STC2 in rat retinal ganglion cells and promoted its secretion. STC2 protein induced the expression and secretion of VEGF in rat retinal ganglion cells, and VEGF had certain interaction with STC2. CONCLUSION STC2 expression is significantly increased in vitreous tissues of the rats with DR, and is closely related to VEGF.     

Expression of short-chain acyl-CoA dehydrogenase during heart development in rats and relationship with cardiac hypertrophy

AIM： To investigate the expression of short-chain acyl-CoA dehydrogenase during the heart deve-lopment in rats and to analyze the relationship between short-chain acyl-CoA dehydrogenase and cardiac hypertrophy in spontaneously hypertensive rats (SHR). METHODS：The expression and activity of short-chain acyl-CoA dehydrogenase in the hearts of Wistar rats with different ages were measured. Free fatty acids in serum and cardiac muscles were also determined. RESULTS：Compared with the fetal rats of 19 d, the expression and activity of short-chain acyl-CoA dehydrogenase in the postnatal rats of 1 d, 2 weeks, 6 weeks and 16 weeks were increased, and free fatty acids in the serum and myocardium were obviously decreased. The difference began in evidence from the age of 2 weeks. The expression of short-chain acyl-CoA dehydrogenase was significantly up-regulated with negative correlation to free fatty acids in the serum and myocardium during heart development. Systolic blood pressure was similar in 2-week-old SHR and WKY rats, which significantly increased in SHR of 6 weeks and 16 weeks old compared with the age-matched WKY rats. The ratio of left ventricular weight to body weight was markedly elevated in SHR of 2 weeks, 6 weeks and 16 weeks old compared with the age-matched WKY rats, indicating that the appearance of cardiac hypertrophy occurred before the development of hypertension in SHR. Compared with the age-matched WKY rats, the expression and activity of short-chain acyl-CoA dehydrogenase were decreased and free fatty acids in the serum and myocardium were obviously higher in SHR. The expression of short-chain acyl-CoA dehydrogenase was significantly down-regulated with a negative correlation to free fatty acids in the serum and myocardium of SHR. CONCLUSION：The expression of short-chain acyl-CoA dehydrogenase is increased during the heart development, which may be associated with the increase in cardiac fatty acid utilization. The down-regulated expression of short-chain acyl-CoA dehydrogenase in the hypertrophic heart may be responsible for the recapitulation of fetal energy metabolism.     

Expression of PARP-1 in epithelial ovarian cancer and its relationship with epithelial-mesenchymal transition

AIM: To investigate the expression of poly(ADP-ribose) polymerase-1(PARP-1) in the epithelial ovarian cancer(EOC) and its relationship with epithelial-mesenchymal transition(EMT). METHODS: The expression of PARP-1, E-cadherin, vimentin and Snail was detected in the EOC and benign ovarian tumor tissues by immunohistochemical method and real-time PCR. The expression of PARP-1, E-cadherin, vimentin and Snail proteins in the SKOV3 cells treated with efficient PARP-1 inhibitor PJ34 was determined by Western blotting. RESULTS: The positive expression rates of PARP-1, vimentin and Snail were significantly higher in the EOC than that in the benign ovarian tumor tissues, whereas the positive expression rate of E-cadherin was the opposite(P<0.05). The expression of PARP-1, E-cadherin, vimentin and Snail in the EOC was associated with the histological grade, clinical stage and lymphatic metastasis(P<0.05), but no relationship with age and pathological types was observed. The expression of E-cadherin in the EOC was negatively co-related to that of PARP-1. In contrast, the expression of vimentin and Snail in the EOC was positively co-related to that of PARP-1. The relative mRNA expression of PARP-1, vimentin and Snail in the EOC was significantly higher than that in the benign ovarian tumor tissues(P<0.05), while the mRNA expression of E-cadherin in the EOC was remarkably lower than that in the benign ovarian tumor tissues(P<0.05). The protein expression of PARP-1, vimentin and Snail in the SKOV3 cells was significantly decreased(P<0.05), while E-cadherin protein was increased after treated with PJ34(P<0.05). CONCLUSION: PARP-1 may contribute to the onset of EMT in the EOC by regulating the expression of E-cadherin, vimentin and Snail. The role of PARP-1, which is relevant to EMT, might be important in the development of ovarian cancer.     

Effect of breviscapine on the oxidative stress in the liver and kidney in diabetic rats

AIM: To study the effect of breviscapine on the oxidative stress in the liver and kidney in diabetic rats. METHODS: Diabetes was induced by injection of streptozotocin (STZ). Rats were randomly divided into three groups: control group, model group, model group treated with breviscapine. 8 weeks after STZ injection, liver lesion was evaluated using HE, oil red O staining and kideny lesion using PAS staining. Malondiadehyde (MDA) levels and antioxidant activities in liver and kidney tissue were determined by spectrophotometric method. RESULTS: Light microscopy in HE staining showed that liver fatty score was significantly lower in the breviscapine group compared with model animals (0.55±0.43 vs 1.54±0.65, P<0.01). In model group, the presence of cytoplasmic lipid deposits was confirmed by oil red O staining, and these changes were significantly lower in the breviscapine group than those in the model group (0.75±0.66 vs 2.11±0.82, P<0.01). In addition, increased kidney weight (KW), KW/body weight (KW/BW), 24 h albumin excretion rate (AER) and glomerular area (AG), glomerular volume (VG) as well as mesangial area (AM) on histological examination of the kidney significantly attenuated by treatment with breviscapine (P<0.05, P<0.01). Levels of MDA were higher and superoxide diamutase (SOD), catalase (CAT) as well as glutathione peroxidase (GSH-Px) activities were significantly lower in liver and kidney tissue in model rats than those in control group. Breviscapine administration could all remit these changes (P<0.05). CONCLUSION: The mechanism of protective effect of breviscapine on liver and kidney may be at least partly correlated with the suppression of increase in oxidative stress in diabetic rats.     

Expression of Sonic hedgehog pathway-related genes in kidney tissues of rats with unilateral ureteral obstruction

AIM: To investigate the role of Sonic hedgehog (Shh) signaling pathway in renal interstitial fibrosis in the rats with unilateral ureteral obstruction (UUO). METHODS: Forty-eight male Sprague-Dawley rats were divided randomly into sham operation group and UUO model group with 24 rats each. The kidneys were excised on day 3, 7, and 14, and the deposition of collagen fiber in the kidneys was detected with HE and Masson staining. Immunohistochemical analysis was performed to evaluate the expression of Shh signaling pathway-related proteins, including Shh, Smo,Ptch1 and Gli1. The contents of TGF-β₁ and Shh in the kidney tissues were determined by ELISA. Real-time RT-PCR was used to detect the mRNA expression of TGF-β₁, Col I, Col III and Shh signaling-related genes.RESULTS: Fibrosis observed with HE and Masson staining was obviously increased in UUO kidneys, and aggravated as time prolonged. The contents of TGF-β₁, Col I and Col III were also increased. In addition, the expression of Shh, Smo and Gli1 was markedly increased in obstructive kidneys, and the expression of Ptch1 was decreased (P<0.01), suggesting that Shh signaling was activated. The level of Shh in UUO rats was associated with the content of TGF-β₁. CONCLUSION: Shh signaling is activated in the progress of renal interstitial fibrosis in UUO rats, and the possible mechanism triggering the fibrogenic response is that Shh signaling promotes the expression of TGF-β₁.     

Expression of BMP-7 and its receptors in rats with unilateral ureteral obstruction

AIM:To explore the expression changes of b one morphogenetic protein-7 (BMP-7) and its receptors (BMPR-Ⅱ,ALK-2,ALK-3,A LK-6) in the renal tubulo-interstitial lesions induced by unilateral ureteral ob struction (UUO).METHODS:Rats were divided into normal control,sham operation a nd UUO groups,and sacrificed at postoperative day 1,3,7 and 14.The mRNA leve ls of BMP-7,BMPR-Ⅱ,ALK-2,ALK-3 and ALK-6 were examined by RT-PCR.The protei n expression site and level of BMP-7 was detected by immunohistochemistry staini ng.RESULTS:Compared to sham operation group,the mRNA levels of BM P-7,BMPR-Ⅱ,ALK-2 and ALK-3 were significantly decreased,but the change of AL K-6 mRNA was not marked in UUO rats.The reduction of mRNA expression levels of BMP-7,BMPR-Ⅱ,ALK-2 and ALK-3 in the kidney tissue aggravated along with the d elayed post-operated days.The results of immunohistochemistry staining indicate d that BMP-7 mainly expressed in renal tubular and interstitial,rarely in glome ruli.In UUO rats,the protein expression of BMP-7 decreased in varying degrees according to the post-operated days.CONCLUSION:The loss of BMP-7 and its receptors (BMPR-Ⅱ,ALK-2,ALK-3) were observed in the early phase of fibrotic process and this may play a very important role in mediating the renal tubulointerstital fibrosis.     

Effect of tissue kallikrein gene treatment on blood pressure in type 2 diabetic rats and its mechanism

AIM:To study the effect of tissue kallikrein gene (HK) treatment on blood pressure in type 2 diabetic rats and its mechanism. METHODS:Male Wistar rats were injected with low dose streptozotocin and fed with diets enriched in fat and sugar to form type 2 diabetic model. Recombinant adeno-associated viral vectors (rAAV)-mediated HK gene (HK group) or LacZ gene (LacZ group) was introduced to the diabetic rats. The systolic blood pressure was measured every 2 weeks. The acetylcholine (Ach)-dependent vasodilation response, the synthesis of nitric oxide (NO), the expression of endothelin-1 (ET-1) and endothelin-A receptor (ETA-R) in the aorta were detected. RESULTS:(1) Systolic blood pressure was significantly higher in diabetic rats than that in normal control rats. In HK group, systolic blood pressure was significantly reduced within 2 weeks after injection with rAAV·HK, reached near normal levels at 4 weeks and kept until the experiments ended (16 weeks). (2) In LacZ group, Ach-dependent vasodilation response of isolated aorta was markedly decreased than that in HK group (P<0.01). (3) The concentration of NO in the aorta of HK group were significantly higher than those in LacZ group. The expression of ET-1 and ETA-R mRNA were significantly decreased in HK group compared with those in LacZ group (P<0.01). CONCLUSION:rAAV-mediated HK gene delivery efficiently lowed blood pressure and attenuated the endothelial function partly through increasing the concentration of NO and inhibiting the expression of ET-1 and ETA-R of aorta in type 2 diabetic rats.