冬虫夏草菌粉对5/6肾大部切除大鼠肾脏纤维化的抑制作用及机制

目的 探讨冬虫夏草菌粉对5/6肾大部切除术大鼠肾脏纤维化的抑制作用及其可能机制.方法 30只雄性SD大鼠随机分为3组:假手术组(Sham组,n=10)、5/6肾大部切除模型组(SNx组,n=10)以及5/6肾大部切除+冬虫夏草菌粉干预组(CS组,n=10).术前及术后4、8、12周分别检测大鼠体质量、尿蛋白量变化,并于术后第12周末处死大鼠,检测血尿素氮、肌酐变化,取肾组织切片行HE、Masson染色观察肾脏病理变化,免疫组化观察转化生长因子β1(TGF-β1)及其Ⅰ型受体(TβR Ⅰ)、Ⅱ型受体(TβR Ⅱ)的表达,免疫荧光观察E-c adherin、α-SMA的表达,Western印迹法检测肾脏组织TGF-β1、TβR Ⅰ、TβR Ⅱ、磷酸化(p)Smad2/3、Smad7、E钙黏蛋白(E-cadherin)、α平滑肌肌动蛋白(α-SMA)的表达.结果 术后CS组大鼠的体质量高于SNx组,尿蛋白量及血尿素氮、血肌酐低于SNx组.肾脏组织病理分析显示,CS组肾小球硬化、肾小管间质损伤程度均显著低于SNx组(均P＜0.01).CS组TGF-β1、TβR Ⅰ、TβR Ⅱ、p-Smad2/3蛋白表达量均显著低于SNx组(均P＜0.05),E-cadherin蛋白表达量显著高于SNx组(P＜0.05),α-SMA蛋白表达量显著低于SNx组(P＜0.05),Smad7蛋白表达量显著高于SNx组(P＜0.05).结论 冬虫夏草菌粉对5/6肾大部切除大鼠肾脏纤维化具有明显的抑制作用,其机制可能是与其抑制TGF-β1及其下游信号通路以及抑制EMT的发生有关.

Effect of Cordyceps sinensis on renal fibrosis in 5/6 subtotal nephrectomy rats and its possible mechanism

Objective To investigate the effect of Cordyceps sinensis on renal fibrosis and its possible mechanism. Methods Thirty Sprague - Dawley rats were randomly divided into three groups: Sham operation group (Sham，n＝10), 5/6 subtotal nephrectomy group (SNx, n＝10), and 5/6 subtotal nephrectomy treated with Cordyceps sinensis group (CS, n＝10). Body weights were assessed and 24 - hour urine excretion was collected before and every four weeks after surgery. Rats were sacrificed at 12 weeks after surgery. Blood samples were taken for biochemical study, and kidney tissues were used for HE and Masson stains to assess histological changes. Immunohistochemical staining was used to detect the expression of transforming growth factor β1 (TGF-β1) and its receptors of type Ⅰ(TβRⅠ), type Ⅱ (TβRⅡ). Immunofluorescence was used to detect E-cadherin and α-SMA. The relative protein level of TGF-β1, TβRⅠ, TβRⅡ, p-Smad2/3, Smad7, E-cadherin, α-SMA were examined by Western blotting. Results CS group had higher body weights and lower urinary protein, BUN and Scr level compared with SNx group. Glomerulosclerosis index and tubulointerstitial injury score were significantly reduced in CS group compared with those in SNx group (all P＜0.05). The protein expressions of TGF-β1,TβRⅠ, TβRⅡ, p-Smad2/3 were decreased in CS group compared with those in SNx group (all P＜0.05). CS treatment up-regulated the expression of E-cadherin, Smad7 and down - regulated the expression of α - SMA compared with that in SNx group (all P＜0.05). Conclusion Cordyceps sinensis has inhibitory effect on renal fibrosis in 5/6 subtotal nephrectomy rat model, which might be related with the suppression of TGF-β1 signal pathway.