红景天苷对链尿佐菌素诱导的糖尿病肾病大鼠肾间质纤维化的改善作用及机制研究

目的探究红景天苷(salidroside, SAL)对糖尿病肾病(diabetic nephropathy,DN)大鼠肾纤维化的改善作用及其机制。方法将60只雄性SD大鼠随机分为对照组、糖尿病肾病模型组、红景天苷低中高剂量干预组,采用链尿佐菌素(streptozotocin, STZ)辅以摘除右肾的方法建立大鼠糖尿病肾病模型,红景天苷组大鼠分别灌胃50、100、200 mg/kg红景天苷。12周后摘取肾脏,HE染色检测肾脏病理损伤;试剂盒检测尿蛋白、尿肌酐(urine creatine, Ucr),血清尿素氮(blood urea nitrogen, BUN)及丙二醛(malondialdehyde, MDA)、超氧化物歧化酶(superoxide dismutase, SOD)和谷胱甘肽过氧化物酶(glutathione peroxidase, GSH-Px)的浓度;免疫印迹检测Ⅳ型胶原蛋白(collagenⅣ)、纤连蛋白(fibronectin)、E-钙黏蛋白(E-cadherin)、α-平滑肌肌动蛋白(α-smooth muscle actin,α-SMA)、N-钙黏蛋白(N-cadherin)、Smad2、Smad3、磷酸化-Smad2 (phosphorylated-Smad2, p-Smad2)、p-Smad3和转化生长因子-β1 (transforming growth factor-β1,TGF-β1)的表达。结果与对照组比较,模型组大鼠肾损伤加重,尿白蛋白、Ucr和BUN浓度明显升高,肾组织凋亡细胞和caspase-3阳性细胞显著增多,差异均有统计学意义(P<0.01);与模型组比较,100和200 mg/kg红景天苷组肾脏损伤明显减轻,尿白蛋白、Ucr和BUN浓度显著降低,肾组织凋亡细胞和caspase-3阳性细胞明显减少,差异均有统计学意义(P<0.05或P<0.01)。50 mg/kg红景天苷能显著升高糖尿病肾病模型大鼠SOD浓度,100和200 mg/kg红景天苷能显著升高糖尿病肾病模型大鼠SOD和GSH-Px浓度并降低MDA浓度;同时,100和200 mg/kg红景天苷还能明显抑制糖尿病肾病模型大鼠肾组织collagenⅣ、纤连蛋白、α-SMA和N-cadherin的表达,诱导E-cadherin表达;此外,100和200 mg/kg红景天苷可显著降低糖尿病肾病模型大鼠p-Smad2/Smad2、p-Smad3/Smad3的比值和TGF-β1的表达水平,差异均有统计学意义(P<0.05或P<0.01)。结论红景天苷能抑制链尿佐菌素诱导的糖尿病肾病模型大鼠肾纤维化,作用机制可能与抑制TGF-β1/Smad通路有关。

Effects and mechanism of salidroside on streptozotocin-induced mode rats of diabetic nephropathy

OBJECTIVE To investigate the effects and mechanism of salidroside(SAL)on model rats of diabetic nephropathy(DN).METHODS Rats were divided into control,model,SAL(50 mg/kg),SAL(100 mg/kg)and SAL(200 mg/kg)groups.The rats beside in control group were injected with streptozotocin(STZ)combined with right nephrectomy.And rats in SAL(50,100,200 mg/kg)groups were received gavage with SAL(50,100,200 mg/kg).After 12 weeks,rats were sacrificed and kidneys were collected.HE staining was performed for renal injury,the concentrations of urine protein,urine creatine(Ucr),blood urea nitrogen(BUN),malondialdehyde(MDA),superoxide dismutase(SOD)and glutathione peroxidase(GSH-Px)were measured by kits.Western blot was used to measure the protein levels of CollagenⅣ,fibronectin,E-cadherin,α-smooth muscle actin(α-SMA),N-cadherin,Smad2、Smad3,phosphorylated-Smad2(p-Smad2),p-Smad3 and transforming growth factor-β1(TGF-β1).RESULTS Compared with control group,the renal injury of rats in model group was aggravated,the concentrations of urine protein,Ucr and BUN were elevated significantly,the apoptosis cells and positive cells of caspase-3 were increased;compared with model group,the renal injury of rats in SAL(100,200 mg/kg)groups were alleviated markedly,the concentrations of urine protein,Ucr and BUN were reduced,the apoptosis cells and positive cells of caspase-3 were decreased notably.SAL(50 mg/kg)increased the concentration of SOD in DN model rats,SAL(100,200 mg/kg)increased the concentrations of SOD and GSH-Px,decreased the level of MDA.Meanwhile,the inhibition of collagenⅣ,fibronrctin,α-SMA,and N-cadherin and the induction of E-cadherin in DN rats were induced by SAL(100,200 mg/kg).In addition,SAL(100,200 mg/kg)reduced the ratio of p-Smad2/Smad2,p-Smad3/Smad3 and the level of TGF-β1(P<0.05 or P<0.01).CONCLUSION SAL can inhibit renal fibrosis of STZ-induced DN model rats,and the mechanism may be related to inhibition of TGF-β1/Smad pathway.