Effects of transplantation of adipose stromal vascular fraction on cardiac function in adriamycin-induced heart failure rats

AIM: To investigate the effects of transplantation of adipose stromal vascular fraction (SVF) on the cardiac function in adriamycin-induced heart failure rats. METHODS: SVF was isolated from adipose tissue of a Sprague-Dawley (SD) rat by collagenase digestion and marked with green fluorescent protein (GFP) in vitro. Twenty-eight SD rats were randomized into normal control group (n=8), adriamycin control group (n=10) and SVF treatment group (n=10). Adriamycin at dose of 15 mg/kg was intraperitoneally injected into the rats twice a week for 4 weeks to induce heart failure. SVF cells (05 mL, 1×107/L) were injected via penis vein, and PBS vehicle was injected into the control animals in the same way. Four weeks later, the cardiac function was determined by multichannel physiologic recorder via cardiac catheterization. SVF was demonstrated in the myocardium by frozen section fluorescence microscopy. The CD31 expression was determined by an immunohistochemical test. RESULTS: Compared with adriamycin control group, SVF transplantation increased left ventricular peak systolic pressure ［LVSP, （13565±21.58) mmHg vs (10558±2262) mmHg, P<005］, left ventricular pressure maximal rise rate ［+dp/dtmax, (4 81565±56624) mmHg/s vs (3 53550±46528) mmHg/s, P<005］, and left ventricular pressure maximal decline rate ［-dp/dtmax, (3 67756±46775) mmHg/s vs (2 73865±51251) mmHg/s, P<005］. The results of the CD31 immunohistochemical test showed that the nuclear staining and granule distribution were more uniform, and the number of blood vessels per visual field increased in SVF treatment group as compared with adriamycin control group (P<005). CONCLUSION: SVF transplantation improves the cardiac function in the rat model of heart failure, possibly and partly through the promotion of myocardial neovascularization.     

Effects of Zhenwu decoction on rat kidney injury induced by adriamycin

AIM: To observe the effects of Zhenwu decoction on the expression of podocin and nephrin in podocytes of adriamycin nephropathy (AN) rats, and to clarify the mechanism of Zhenwu decoction in decreasing adriamycin-induced proteinuria in rats. METHODS:Biochemical assay and pathological observation (HE staining, Masson trichrome staining and transmission electron microscopy) were used to evaluate the effects of Zhenwu decoction on renal function, pathological morphology and hydroxyproline (Hyp) content in AN rats with renal fibrosis. Western blotting was used to observe the effect of Zhenwu decoction on the expression of podocin and nephrin which are marker proteins in podocytes. RESULTS:In model group, the levels of urinary total protein (TP), blood urea nitrogen (BUN), serum creatinine (SCr) and renal Hyp were significantly increased, and the clearance of creatinine (CCr) level was decreased (P<0.05). The expression of podocin and nephrin was significantly decreased (P<0.05). Atrophic renal tubules, thickened basement membranes, fusion of foot processes, concentrating renal glomerules, expansion of some renal tubules, degeneration of renal tubular epithelial cells, protein casts, and proliferation of fibroblasts and infiltration of inflammatory cells in renal interstitium were also observed. After treatment with drugs (Zhenwu decoction and valsartan), the above-mentioned parameters were significantly changed. TP, BUN, SCr and Hyp were down-regulated to different levels, and CCr was significantly up-regulated (P<0.05). The expression of podocin and nephrin was up-regulated by treatment with Zhenwu decoction, and renal histological changes were alleviated compared with model group. CONCLUSION: Zhenwu decoction can reduce Hyp content in kidney tissue, alleviate kidney histological changes, and improve renal function in AN rats. It might protect kidney against adriamycin-induced proteinuria via increasing the expression of podocin and nephrin in podocytes.     

Mechanisms for a decrease in mortality of LPS-challenged mice by rhynchophylline

AIM: To observe effect of rhynchophylline （Rhy） on mortality and organ injury in endotoxemic mice and further investigate the mechanisms of its actions. METHODS: Male mice were randomly assigned into control, LPS, Rhy +LPS and Rhy group, and injected subcutaneously with normal saline (0.05 mL/10 g), or rhynchophylline once a day for 3 d, 1 h after subcutaneously treatment on day 3, LPS (20 mg/kg) or normal saline was injected intraperitoneally. Survival rate was recorded every 12 h for 6 d. In another experiment, 12 h after LPS injection, the left lung and intestine tissue sections were prepared for histological analysis and the right lung were used to determine the ratio of wet to dry lung tissue weight (W/D),the serum was collected to detect the concentrations of alanine aminotransferase（ALT）, aspartate aminotransferase (AST ), bloodureanitrogen (BUN) and creatinine (Cr). In addition, the concentrations of tumor necrosis factor-α (TNF-α), interleukin-1β(IL-1β) and interleukin-10 (IL-10) in serum at 2 h after LPS challenge were detected by enzyme-linked immunosorbent assay. The concentration of NO in serum at 8 h was detected by enzymic method. The effect of Rhy on survival rate of mice subjected to cecal ligation and puncture (CLP) was also observed. RESULTS: Mortality of mice challenged with LPS alone was higher significantly than that in control at 24 h after LPS challenge, pretreated with Rhy at a dose of 8 or 16 mg/kg increased markedly the survival rate of LPS-challenged mice. However, Rhy at a dose of 8 mg/kg significantly increased mortality of mice subjected to CLP. In the histological analysis, severe inflammation was observed both in the lung and intestine tissues in the LPS group. LPS elevated lung W/D, the levels of ALT, AST, BUN, Cr, TNF-α, IL-1β, IL-10 and NO in serum. Pretreatment with Rhy had no obvious improvement in the lung and intestine tissue injury, and no significant depression in the lung W/D and the serum levels of ALT, AST, BUN, Cr, IL-1β, IL-10 and NO, but decreased the level of TNF-α in serum significantly in LPS -treated mice. CONCLUSION: Pretreatment with Rhy reduces the mortality in endotoxemic mice, but not decrease the mortality of mice challenged with CLP, at least in part, through inhibiting the synthesis and secretion of TNF-α.     

Effect of rhynchophylline on TGF-β1/Smad pathway for processing ventricular remodeling in spontaneously hypertensive rats

AIM: To investigate the effect of rhynchophylline (Rhy) on blood pressure, cardiac hypertrophy and myocardial fibrosis in spontaneously hypertensive rats (SHR). METHODS: Spontaneously hypertensive rats were randomly divided into model group, high dose (10 mg·kg^-1·d^-1) and low dose (2.5 mg·kg^-1·d^-1) group of rhynchophylline, captopril group (17.5 mg·kg^-1·d^-1). Wistar-Kyoto rats were used as normal control. Respectively, systolic blood pressure was measured by tail cuff every 2 weeks. After 10 weeks, heart weight index and left ventricular weight index were calculated. The myocardial hydroxyproline and plasma angiotensin Ⅱ were detected. Moreover, basic myocardial histopathological changes and myocardial collagen fibres were observed by HE staining and Masson staining, respectively. The protein expression of TGF-β₁ and Smad3 in the myocardium was measured by the methods of immunohistochemistry and Western blot. RESULTS: Compared with SHR model group, Rhy significantly reduced blood pressure (P<0.05), the levels of HYP in the myocardium (P<0.05) and the levels of AngⅡ in the plasma (P<0.01). The pathological damages of the myocardial tissues and collagen deposition were attenuated. The protein expression of TGF-β₁ and Smad3 was significantly reduced by the treatment with Rhy (P<0.01). CONCLUSION: Rhynchophylline reduces blood pressure and adjusts to improve ventricular remodeling of SHR. The mechanism may be involved in the TGF-β₁/Smad pathway and reducing AngⅡ content.     

Effects of simvastatin on expression of Bcl-2 and Bax in myocardium of rats with renal ischemia-reperfusion injury

AIM: To observe the effect of simvastatin on myocardial tissue after renal ischemia-reperfusion injury and its mechanism. METHODS: A rat model of renal ischemia-reperfusion injury was prepared by clamping the bilateral renal arteries for 45 min. The rats (n=36) were randomly divided into sham operation group, renal ischemia-reperfusion (I/R) group and simvastatin group with 12 rats in each group. The content of serum creatinine (SCr), blood urea nitrogen (BUN) and myocardial tissue malondialdehyde (MDA), the myocardial activity of lactate dehydrogenase (LDH), creatine kinase (CK) and superoxide dismutase (SOD), and the myocardial protein expression of Bcl-2 and Bax were detected. RESULTS: Compared with sham operation group, the content of SCr, BUN and myocardial MDA, and the myocardial activity of LDH and CK in I/R group were significantly increased (P<0.05), and the activity of SOD was significantly decreased (P<0.05). Compared with I/R group, the content of SCr, BUN and myocardial MDA, and the myocardial activity of LDH and CK in simvastatin group were significantly decreased (P<0.05), while SOD activity was enhanced (P<0.05). The protein expression of Bcl-2 and Bax in sham operation group was less than that in I/R group (P<0.05), and the protein level of Bax in simvastatin group was significantly lower than that in I/R group (P<0.05), while the protein level of Bcl-2 was increased (P<0.05). CONCLUSION: Simvastatin has a protective effect on the myocardium of the rats with renal ischemia-reperfusion injury, and the protective mechanism may be related to the elimination of free radicals by simvastatin, increase in the protein expression of Bcl-2 and decrease in the protein expression of Bax.     

Development and formation of urinary calculi and renal injury in rats administered with melamine

AIM: To investigate the formation of urinary calculi and the development of renal injury in rats administered with melamine.METHODS: The renal lesions and the formation of urinary calculi induced by administration of melamine were investigated in male SD rats. The animals, 6 weeks old at the beginning of the experiment, were treated with 3%(W/W) melamine in the diet for 12 weeks followed by a 4-week period without the chemical. The treatment with Uralyt-U was also performed.RESULTS: The total observation time was 16 weeks. The renal lesions (100%) and urinary calculus formation (54.5%) were observed in the rats given 3% melamine. However, carcinomas of the urinary bladder were not found. Withdrawal of melamine resulted in the improvement of renal lesions and the vanishing of the urinary calculus. Treatment with Uralyt-U improved the renal function. CONCLUSION: It is confirmed that melamine at the dose of 3% in the diet induces the formation of urinary calculi and development of renal injury in rats. Urinary calculi are not the direct cause of renal injury. Withdrawal of melamine results in improvement of renal lesions and vanishing of the urinary calculi.     

Heme oxygenase-1 protects renal function in septic rats via influencing expression of thrombomodulin

AIM: To investigate the protective effect of heme oxygenase-1 (HO-1) on the kidney of septic rats and the influence of HO-1 on the expression of thrombomodulin (TM) in the kidney. METHODS: Sepsis in rats was developed with cecal ligation and puncture (CLP). The septic rats were randomly divided into sham group, CLP group, CLP+HO-1 inducer group and CLP+HO-1 inhibitor group (n=18). The plasma levels of creatinine (Cr), cystatin-C (Cys-C), carboxyhemoglobin (COHb), tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β) and TM, and the changes of prothrombin time (PT) and activated partial thromboplastin time (APTT) in each group were measured. Histopathological examination was performed in the kidney. The expression of TM in the kidney tissue was detected by Western blot. RESULTS: Compared with sham group, significantly elevated plasma levels of Cr, Cys-C, TNF-α, IL-1β and TM (P<0.05), shortened PT and APTT (P<0.05), significantly increased microthrombus formation, and lowered TM expression in the kidney (P<0.05) of CLP group were observed. The administration of hemin lowered the plasma levels of Cr, Cys-C, TNF-α, IL-1β and TM (P<0.05), prolonged PT and APTT (P<0.05), attenuated microthrombus formation, and up-regulated the expression of TM in the kidney (P<0.05). In contrast, ZnPP had the opposite effects. CONCLUSION: HO-1 increases the expression of TM in the kidney and exerts anticoagulatory and antiinflammatory effects, thereby improving renal function in the septic rats.     

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.     

Seipin gene deficiency induces renal injury in mice

AIM:To investigate the effects of seipin gene deficiency on renal injury and the possible mechanisms in seipin-/- mice. METHODS:Six-month-old male seipin knockout (seipin-/-) and wild-type (WT) mice (n=8) were used to study 24 h urinary albumin excretion (UAE), renal functions, pathological changes, and plasma leptin and adiponectin levels. Seipin mRNA expression in different tissues and each part of the kidney was also measured in WT mice. RESULTS:Real-time PCR analysis showed seipin mRNA expression in WT mice was higher in adipose tissue and testicles, and was also found in the kidney, which was mainly in glomeruli. Compared with control group, seipin-/- group showed increased kidney weight/tibia length (P<0.01), 24 h UAE (P<0.01), creatinine clearance (P<0.01), and glomerular and mesangial surface area (P<0.05). Both plasma leptin (P<0.01) and adiponectin (P<0.05) levels were significantly decreased in seipin-/- mice. CONCLUSION: Seipin gene deficiency in mice leads to renal injury probably by decreasing plasma leptin and adiponectin levels due to lack of adipose tissue.     

Effects of ethane 1,2-dimethanesulfonate preconditioning on renal ischemia/reperfusion injury in male rats

AIM: To investigate the effects of ethane 1,2-dimethanesulfonate (EDS) preconditioning on renal ischemia/reperfusion (I/R) injury in male Sprague-Dawley (SD) rats. METHODS: Male SD rats (n=48) were randomly assigned to 6 groups: blank, sham, I/R, EDS+I/R, EDS+testosterone (TST)+I/R, and castration (Cast)+I/R. The renal pedicles were bilaterally occluded with a microvascular clamp for 45 min to establish renal I/R-induced injury model. Bilateral orchiectomy was conducted 2 weeks before surgery. EDS (75 mg/kg) was intraperitoneally injected 5 d before operation. Blood samples were collected 24 h after reperfusion from the vena orbitalis posterior plexus. Luteinizing hormone (LH), TST, serum creatinine (SCr), blood urea nitrogen (BUN), and kidney injury molecule-1 (KIM-1) were detected. The renal tissues were harvested to measure the level of TNF-α and the expression of Fas mRNA and caspase-3 protein. RESULTS: Serum TST levels in EDS+I/R group and Cast+I/R group were below the minimum detectable threshold. Compared with other groups, the rats in EDS+I/R group and Cast+I/R group had higher levels of SCr, BUN and KIM-1 (P<0.05). SCr and BUN levels showed no significant difference between EDS+I/R group and Cast+I/R group (P>0.05), but KIM-1 level in EDS+I/R group was lower than that in Cast+I/R group (P<0.05). After reperfusion for 24 h, the levels of TST and LH in EDS+I/R group, Cast+I/R group and EDS+TST+I/R group were lower than those 1 h before operation (P<0.05). Compared with Cast+I/R and I/R group, the TNF-α level and expression of Fas mRNA and caspase-3 protein were significantly decreased in EDS+I/R group (P<0.05). CONCLUSION: EDS preconditioning substantially reduces the serum TST level, thus attenuating I/R-induced acute renal injury. TNF-α-induced Fas/FasL pathway may be involved in this process.     

Effect of renal transporter Glut9 on hyperuricemia in rats induced by fructose

AIM: To explore the effect of renal transporter glucose transporter 9 (Glu9) on hyperuricemia in the rats induced by fructose.METHODS: SD male rats (n=30) were randomly divided into normal group, model group and benzbromarone group, according to the weight. The rats in normal group was given water, while the rats in model group and benzbromarone group were given 10% fructose solution to establish hyperuricemia model. At the same time, the rats in normal group and model group were given a gavage of distilled water, while the rats in benzbromarone group were given benzbromarone at the dose of 20 mg/kg. The rats were sacrificed on the 40th day. The serum uric acid (SUA) and urinary uric acid (UUA) were detected to calculate the clearance rate of uric acid (CUA) in the kidney. The activity of hepatic xanthine oxidase (XOD) was also measured. The expression of renal Glut9 at mRNA and protein levels was determined by RT-qPCR and immunohistochemical staining. RESULTS: From the 20th day to the 40th day, the SUA in model group was significantly higher than that in normal group, but the UUA and CUA had no difference. On the 20th day, the SUA in benzbromarone group was markedly decreased as compared with model group, but UUA and CUA had no significant difference. On the 40th day, the hepatic XOD activity in model group was significantly elevated, and no difference of XOD between model group and the benzbromarone group was observed. Compared with normal group, the protein expression of Glut9 in the renal tissues of model group were markedly increased, and that in benzbromarone group was significantly lower than that in model group. However, no difference of the Glut9 mRNA expression was observed among groups. CONCLUSION: Fructose drinking induces hyperuricemia in rats, which is probably related to the up-regulation of renal Glut9 expression at protein level, and the increase in the reabsorption of uric acid in the kidneys.     

Effect of "Shen Yan Yi Qi Solution" on renal function and histopathology of rats suffering from an experimental nephrotoxic serum nephritis

AIM: To investigate the therapeutic effects of "Shen Yan Yi Qi Solution", a chinese Medicine, on nephrotoxic serum nephritis in the rat.METHODS: Nephrotoxic serum nephritis model of the rat was set up by the Clarke’s method. RESULTS: Proteinuria and renal insufficiency occurred in all rats after nephrotoxic serum (NTS) injection, but symptoms in treatment group were reduced. At 2nd week, the typical linear deposition of IgG along the glomerular basement membrane (GBM) was observed by fluorescence microscopy. Mesangial hyperplasia and crescent formation in glomeruli were also observed by light microscopy. In treatment group, all the above lesions were alleviated. CONCLUSION: It demonstrated that "Shen Yan Yi Qi Solution" might alleviate the pathological change of glomeruli and improve renal function.     

Effects of bFGF on brain edema,nerve function injury and autophagy related protein in rats with traumatic brain injury

AIM:To study the effects of basic fibroblast growth factor (bFGF) on brain edema, nerve function damage and autophagy related proteins in rats with head injury. METHODS:The rat model of craniocerebral injury (CI) was constructed. The rats were divided into control group, CI group, and low-, middle-and high-dose bFGF groups (n=10). The CI model was established in CI group, while the rats in control group were not given epidural impact. The rats in low-dose, middle-dose and high-dose bFGF groups were given bFGF at 2, 4 and 6 μg, respectively, by intraperitoneal injection after 30 min. The neurological function in the rats was evaluated by improved neurological function scoring. The rat brain tissues were taken, and the water content was detected. The levels of tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6) and IL-1β in the brain tissue were measured by ELISA. The malondialdehyde (MDA) content was analyzed by thiobarbituric acid method. The activity of superoxide dismutase (SOD) was examined by WST-8 assay. The glutathine peroxidase (GSH-Px) activity was detected by colorimetric method. The protein levels of autophagy related proteins LC3-Ⅱ and beclin-1 in the brain tissues were determined by Western blot. RESULTS:The neurological function score was increased significantly of the rats in CI group. The rat model of craniocerebral injury was successfully constructed. Neurological function scores in the rats in low-dose, middle-dose and high-dose bFGF groups were reduced, the water content of the brain tissue was also reduced (P<0.05). The levels of TNF-α, IL-6 and IL-1 β were decreased in the brain tissues (P<0.05), the content of MDA was declined (P<0.05), the activities of SOD and GSH-Px were increased (P<0.05), the protein levels of LC3-Ⅱ and beclin-1 were decreased, compared with the untreated rats in CI group (P<0.05). CONCLUSION:bFGF improves the nerve function of the rats with craniocerebral injury, reduces the water content of the brain tissue, reduces the expression of autophagic protein LC3-Ⅱ and beclin-1.The mechanism is related to the inhibition of inflammatory reaction and oxidative damage.     

Effect of tacrolimus on renal ischemia/reperfusion injury in rats

AIM: To investigate the protective effects and mechanism of tacrolimus on renal ischemia/reperfusion(I/R) injury in rats.METHODS: Sixty male Wistar rats were randomly divided into 3 groups: sham-operated group, I/R group and tacrolimus group. After the renal I/R injury model was established, the serum content of creatinine(Cr), tumor necrosis factor-α(TNF-α)and malondialdehyde(MDA) and activity of superoxide dismutase(SOD) were measured at reperfusion time points of 0.5 h, 2 h, 6 h and 24 h. The renal histopathological lesions and the expression of Fas and caspase-3 were observed by the methods of microscopy and immunohistochemistry, respectively.RESULTS: At all the 4 time points, the levels of Cr, TNF-α and MDA in tacrolimus group were lower than those in I/R group(P<0.05). The SOD activity in tacrolimus group was higher than that in I/R group. Compared with I/R group, the renal histopathological lesions were improved, and the levels of Fas and caspase-3 were significantly decreased in tacrolimus group(P<0. 05).CONCLUSION: Tacrolimus inhibits the production of free radical, the expression of TNF-α and apoptosis of renal tubular epithelial cells in renal I/R injury in rats, indicating that tacrolimus has protective function against renal I/R injury.     

Expression of calprotectin in rats with renal ischemia-reperfusion injury

AIM: To investigate the expression of calprotectin(CALP) in the rats with renal ischemia-reperfusion injury(IRI). METHODS: Male Sprague-Dawley rats were randomly divided into sham operation and IRI group(n=25 in each group). Blood samples and the kidneys were obtained at 6 h, 12 h, 24 h, 48 h and 72 h after reperfusion. The pathological changes of the kidneys were observed. The serum concentrations of blood urea nitrogen(BUN) and serum creatinine(SCr) were measured. The serum levels of CALP, tumor necrosis factor-α(TNF-α) and interleukin-6(IL-6) were detected by ELISA, and the expression of CALP, Toll-like receptor 4(TLR4) and NF-κB p65 in the renal tissues were determined by the methods of immunohistochemistry and Western blot. RESULTS: Different serial ischemia changes were observed in the renal tissues, mainly in the renal tubular epithelial cells and the mesenchyma, with the infiltration of inflammatory cells. The serum levels of BUN, SCr, CALP, TNF-α and IL-6 in IRI group were markedly increased as compared with sham group(P<0.05). The protein expression of CALP, TLR4 and NF-κB p65 in the renal tubular epithelial cells in IRI group was greatly enhanced in comparison with that in sham group(P<0.05). CONCLUSION: The serum concentrations of CALP, TNF-α and IL-6, and the protein expression levels of CALP, TLR4 and NF-κB p65 in the renal tissue are significantly increased in the rats with IRI, suggesting that calprotectin plays an important role in the inflammation in rats with IRI.     

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.     

Up-regulation of CD36 induced by casein-induced inflammation promotes renal injury in mice

AIM: To investigate the role of CD36 in casein-induced mouse renal injury.METHODS: Eight-week-old male C57BL/6J mice and CD36 knockout (CD36KO) mice were randomly divided into C57BL/6J saline injection group, C57BL/6J casein injection group and CD36KO casein injection group (n=8 in each group). After 14 weeks of treatment with high-fat diet, the mouse serum, 24 h urine and kidney tissue samples were collected for analysis. The serum content of tumor necrosis factor-α (TNF-α) was measured by ELISA. The renal function markers in the serum and urine were determined by an automatic biochemical analyzer. The pathological changes of the kidney were observed by HE staining and Masson staining. The expression of CD36 and cytokines/chemokines (TNF-α, IL-6 and MCP-1) at mRNA and protein levels in the renal tissues were determined by real-time PCR and Western blot. The content of tissue hydrogen peroxide (H₂O₂) was measured by a commercial kit. The protein levels of Nrf2 and TGF-β1 in the renal tissues were measured by immunohistochemical staining.RESULTS: Compared with saline injection group, casein injection increased the level of TNF-α in the serum and in the kidney tissues of C57BL/6J mice (P<0.05), suggesting that casein injection successfully induced chronic inflammation in C57BL/6J mice. Casein injection also promoted the protein expression of CD36 and TGF-β1 in the renal tissues of the C57BL/6J mice, accompanied with glomerular sclerosis, proteinuria, increased serum creatinine content, increased H₂O₂ content, and decreased Nrf2 protein level and the ability of antioxidant in the kidneys (P<0.05). Furthermore, CD36 deficiency protected the mice from casein-induced renal injury, as evidenced by improved kidney pathological changes and decreased proteinuria. The content of H₂O₂ in the kidneys of casein-treated CD36 knockout mice was also lower than that in casein-treated C57BL/6J mice.CONCLUSION: Inflammatory responses promote the oxidative stress and renal injury in a CD36-dependent manner.