艾塞那肽对糖尿病肾病小鼠足细胞的保护作用

目的探讨艾塞那肽对糖尿病肾病小鼠足细胞的作用。方法通过给予C57BL/6J小鼠高脂饮食并注射链脲佐菌素建立糖尿病肾病模型,按随机数字表法将其分为糖尿病肾病对照组(DN组,n=8)、艾塞那肽干预组(DN+Ex组,n=8)。同时将普通饲料喂养的C57BL/6J小鼠作为正常对照组(NC组,n=8)。干预结束后,测定血糖、肾功能和尿微量白蛋白/肌酐比值,采用过碘酸希夫染色(PAS)观察小鼠肾小球病理学改变,实时定量PCR分析肾小球组织中促纤维化分子Ⅳ型胶原蛋白(Collagen Ⅳ)、转化生长因子-β(TGF-β)和纤维连接蛋白(Fibronectin)基因转录水平,免疫荧光染色及电镜观察足细胞损伤及凋亡情况,Western印迹法检测肾小球组织中裂孔膜肾病蛋白(Nephrin)、活化型半胱氨酸天冬氨酸蛋白酶3(Cleaved caspase-3)、蛋白激酶B(Akt)和磷酸化Akt(p-Akt)表达水平。结果与DN组相比,DN+Ex组小鼠尿微量白蛋白/肌酐比值显著降低(P<0.01)。PAS染色及分析发现,艾塞那肽干预治疗改善了糖尿病肾病小鼠的肾小球系膜基质增生和肾小球肥大(P<0.05)。实时定量PCR显示,与DN组小鼠相比,DN+Ex组小鼠的肾小球组织中Collagen Ⅳ、TGF-β和Fibronectin基因表达下调(P<0.01)。免疫荧光染色和电镜显示,艾塞那肽干预治疗改善了糖尿病肾病小鼠的足细胞损伤及凋亡。Western印迹法发现,艾塞那肽干预后糖尿病小鼠肾小球组织中的Nephrin水平升高(P<0.01)、Cleaved caspase-3水平下降(P<0.01)、p-Akt水平升高(P<0.01)。结论艾塞那肽能够改善糖尿病肾病小鼠的足细胞损伤及凋亡,减少蛋白尿,从而延缓糖尿病肾病的进展。这种保护作用可能与激活肾小球中磷酸肌醇3-激酶(PI3K)/Akt信号通路有关。

Protective effect of exenatide on podocyte in diabetic nephropathy mice

Objective To investigate the effects of exenatide on podocyte in diabetic nephropathy mice.Methods Diabetic nephropathy mice models were induced by using streptozocin-treated C57BL/6J mice on high fat diets,which were randomized by random number table to diabetic nephropathy control group(DN group,n=8)and exenatide treatment diabetic nephropathy group(DN+Ex group,n=8).The C57BL/6J mice on normal chow diet were used as normal control group(NC group,n=8).After the intervention,blood glucose,renal function,and urine albumin/creatinine ratio were measured.Pathological glomerular changes were observed by pexiodic acid-Schiff stain(PAS)staining.The mRNA expression of profibrotic molecules CollagenⅣ,transforming growth factor-β(TGF-β),and Fibronectin in glomerular lysates were measured by realtime quantitative PCR(RT-PCR).Podocyte injury and apoptosis were evaluated by immunofluorescent staining and transmission electron microscopy.The expression of Nephrin,Cleaved caspase-3,protein kinase B(Akt),and phosphorylated Akt(p-Akt)in glomerular lysates were examined by western blotting.Results Compared with the DN group,urine albumin/creatinine ratio was significantly decreased in the DN+Ex group(P<0.01).PAS staining and analysis found that exenatide administration ameliorated mesangial matrix expansion and glomerular hypertrophyin in DN group(P<0.05).RT-PCR analyses showed that the glomerular expression for Fibronectin,TGF-β,and CollagenⅣwere significantly decreased in the DN+Ex group compared with the DN group(P<0.01).Immunofluorescent staining and transmission electron microscopy revealed that exenatide treatment improved podocyte injury and apoptosis in DN group.Western blotting analyses showed that exenatide increased the Nephrin expression,decreased the Cleaved caspase-3 expression,increased the p-Akt expression in glomerular lysatesin diabetic nephropathy mice(P<0.01).Conclusion Exenatide attenuates podocyte injury and apoptosis and proteinuria,and prevents the progression of diabetic nephropathy mice.Phosphatidylinositol 3-kinase(PI3K)/Akt pathway in glomerular lysates may be related to the protective effects of exenatide.