目的 基于胰岛素受体底物2（insulin receptor substrate 2，IRS2）/磷脂酰肌醇-3-激酶（phosphatidylinositol-3-kinase，PI3K）/叉头框蛋白O4（forkhead box O4，FOXO4）信号通路探讨复方仙草颗粒抑制糖尿病肾病（diabetic nephropathy，DN）大鼠肾足细胞上皮-间充质转化（epithelial-mesenchymal transition，EMT）的作用机制。方法 采用单侧肾切除、高糖高脂饲料喂养及一次性ip链脲佐菌素制备DN模型大鼠，另设置对照组和假手术组，将造模成功的大鼠随机分为模型组、厄贝沙坦（15.75 mg/kg）组和复方仙草颗粒组低、中、高剂量（315.0、472.5、945.0 mg/kg）组，各给药组ig相应药物，连续6周。检测各组大鼠空腹血糖、肾脏指数（kidney index，KI）、尿微量白蛋白/肌酐比值（urinary albumin-to-creatinine ratio，UACR）、尿素氮（blood urea nitrogen，BUN）水平；采用苏木素-伊红（HE）染色法观察肾组织病理变化；采用透射电镜（TEM）观察肾足细胞超微结构变化；采用qRT-PCR和Western blotting检测大鼠肾组织足细胞裂孔膜蛋白（nephrin）、P-钙黏蛋白（P-cadherin）、α-平滑肌肌动蛋白（α-smooth muscle actin，α-SMA）、Desmin、成纤维细胞特异蛋白-1（fibroblast specific protein-1，FSP-1）及IRS2/PI3K/FOXO4信号通路相关因子mRNA和蛋白表达。结果 与对照组比较，模型组大鼠KI、UACR、BUN水平均显著升高（P<0.05），肾小球肥大，肾小管广泛扩张，上皮细胞变性脱落，足突融合或丢失；肾组织nephrin、P-cadherin表达显著降低（P<0.05），α-SMA、Desmin、FSP-1表达显著升高（P<0.05），IRS2/PI3K/FOXO4信号通路相关因子mRNA和蛋白表达均显著降低（P<0.05）。与模型组比较，复方仙草颗粒组大鼠KI、UACR、BUN水平显著降低（P<0.05），肾脏病理结构和足细胞超微结构明显改善；肾组织nephrin、P-cadherin表达显著升高（P<0.05），α-SMA、Desmin、FSP-1表达显著降低（P<0.05），IRS2/PI3K/FOXO4信号通路相关因子mRNA和蛋白表达均显著升高（P<0.05）。结论 复方仙草颗粒能够通过调节IRS2/PI3K/FOXO4信号通路改善DN大鼠肾功能，抑制DN大鼠足细胞EMT，减轻足细胞损伤。

Objective To investigate the mechanism of Compound Xiancao Granules (复方仙草颗粒) on inhibiting epithelial-mesenchymal transition (EMT) of renal podocytes in diabetic nephropathy (DN) rats based on insulin receptor substrate 2 (IRS2)/phosphatidylinositol-3-kinase (PI3K)/forkhead box O4 (FOXO4) signaling pathway. Methods DN model rats were prepared by unilateral nephrectomy, high sugar and high fat diet and one-time ip streptozocin, control group and sham-operated group were set up. Successfully modeled rats were randomly divided into model group, irbesartan (15.75 mg/kg) group, Compound Xiancao Granules low-, medium-and high-dose (315, 472.5, 945 mg/kg) groups, and each administration group was ig corresponding drugs for six weeks. Fasting blood glucose, kidney index (KI), urinary albumin-to-creatinine ratio (UACR) and blood urea nitrogen (BUN) of rats in each group were measured; Hematoxylin-eosin (HE) staining was used to observe histopathology changes in renal; Transmission electron microscopy was used to observe ultrastructural changes in renal pedicle cells; qRT-PCR and Western blotting were used to detect mRNA and protein expressions of nephrin, P-cadherin, α-smooth muscle actin (α-SMA), Desmin, fibroblast specific protein-1 (FSP-1) and IRS2/PI3K/FOXO4 signaling pathway related factors. Results Compared with control group, KI, UACR and BUN in model group were significantly increased (P < 0.05); Glomerular hypertrophy, extensive tubular dilatation, epithelial cell degeneration and shedding, fusion or loss of peduncle were observed; Nephrin and P-cadherin expressions in renal were significantly decreased (P < 0.05), α-SMA, Desmin and FSP-1 expressions were significantly increased (P < 0.05), mRNA and protein expressions of IRS2/PI3K/FOXO4 signaling pathway related factors were significantly decreased (P < 0.05). Compared with model group, KI, UACR and BUN in Compound Xiancao Granules groups were significantly decreased (P < 0.05), renal pathological structure and podocyte ultrastructure were significantly improved; Nephrin and P-cadherin expressions in renal were significantly increased (P < 0.05), α-SMA, Desmin and FSP-1 expressions were significantly decreased (P < 0.05), mRNA and protein expressions of IRS2/PI3K/FOXO4 signaling pathway related factors were significantly increased (P < 0.05). Conclusion Compound Xiancao Granules can improve kidney function in DN rats by regulating IRS2/PI3K/FOXO4 signaling pathway, inhibit EMT of podocytes in DN rats and reduce podocyte injury.

R285.5

国家自然科学基金资助项目（81960913）；广西中医药大学2021年研究生教育创新计划项目区级课题（YCSW2021235）