藏红花素对糖尿病肾病大鼠肾纤维化的影响及机制研究

Effect and mechanism of crocin on renal fibrosis in rats with diabetic nephropathy

[目的]研究藏红花素对糖尿病肾病(DN)大鼠肾纤维化的影响并探索其机制。[方法]通过高糖高脂饲养4周后腹腔注射链尿佐菌素建立DN大鼠模型,将50只模型大鼠随机平均分为模型组(给予生理盐水)、二甲双胍(500 mg/kg)组和藏红花素低、中、高剂量组(25、50、100 mg/kg)组,另设正常对照组(给予生理盐水),连续12周,每日1次灌胃给药。测定空腹血糖(FBG)水平,称量体质量,检测肾功能指标,分别通过苏木精-尹红(HE)染色、马森(Masson)染色进行肾组织病理学和纤维化检查,免疫蛋白印迹法检测克洛索蛋白(Klotho)、转化生长因子-β1(TGF-β1)、磷酸化Smad2(p-Smad2)表达。[结果]与模型组相比,藏红花素中、高剂量组和二甲双胍组体质量升高,FBG、24 h尿蛋白量(UPro)、尿素氮(BUN)、肌酐(Scr)水平降低;肾小球增大、肾间质炎性细胞浸润、系膜和基底膜增生等病变及肾小球、肾间质纤维化均明显改善,胶原容积分数(CVF)降低;Klotho表达上调,TGF-β1、p-Smad2表达下调,差异有统计学意义(P<0.05或P<0.01)。与二甲双胍组比较,藏红花素高剂量组大鼠体质量升高,UPro和BUN、Scr水平降低,CVF降低,Klotho表达上调且TGF-β1、p-Smad2表达下调,差异有统计学意义(P<0.05或P<0.01)。[结论]藏红花素对DN大鼠肾纤维化具有抑制作用,其机制可能与抑制Klotho/TGF-β/Smad信号通路有关。

[Objective]To investigate the effect and mechanism of crocin on renal fibrosis in diabetic nephropathy(DN)rats.[Methods]The DN rat models were prepared by feeding high-fat diet for 4 weeks and intraperitoneal injection of streptozotocin.The 50 rat models were randomly divided into model group(saline),metformin(500 mg/kg)group and crocin low,medium and high dose groups(25,50,100 mg/kg)group;and the normal control group(saline)was set up;the drugs were given once a day for 12 weeks.The body weight,fasting blood sugar level and the renal function index were detected;the renal histopathology and fibrosis were examined by Hematoxylin-Yinhong(HE)staining and Masson staining;the expression of Klotho,transforming growth factor-β1(TGF-β1),phosphorylated Smad2(p-Smad2)were detected by Western blot method.[Results]Compared with model group,the body weight of the rats in the crocin medium-,high-dose group and metformin group was increased,the fasting blood glucose levels,24 h urine protein(UPro),the levels of urea nitrogen(BUN),creatinine(SCr)in serum were decreased;the histopathology such as glomerulus enlargement,renal interstitial inflammatory cell infiltration,mesangial and basement membrane hyperplasia and glomerular,renal interstitial fibrosis were significantly improved,and the collagen volume fraction(CVF)was reduced;the expression of Klotho was up-regulated and the expression of TGF-β1,p-Smad2 were down-regulated,all of the difference were significant(P<0.05 or P<0.01).Compared with metformin group,the body weight of rats in the crocin high-dose group was increased;the UPro and the levels of BUN,SCr in serum were decreased;the CVF was decreased;the expression of Klotho was up-regulated and the expression of TGF-β1,p-Smad2 were down-regulated,all of the difference were significant(P<0.05 or P<0.01).[Conclusion]Crocin has inhibitory effect on renal fibrosis in DN rats,which may be related to the inhibition of Klotho/TGF-β/Smad signaling pathway.