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

关键词:  藏红花素  糖尿病肾病  纤维化  胶原蛋白  Klotho/TGF-β/Smad信号通路

Key words:  crocin  diabetic nephropathy  fibrosis  collagen  Klotho/TGF-β/Smad signaling pathway

摘要:

[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。

Abstract:

[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.