Effect of Huangqisan Pellets on PI3K/Akt/mTOR Signaling Pathway and Autophagy in Kidney of Diabetic Nephropathy Rats / 中国实验方剂学杂志

ABSTRACT

ObjectiveTo investigate the effect of Huangqisan pellets （HQS） on the phosphatidylinositol-3 kinase/protein kinase B/mammalian target of rapamycin （PI3K/Akt/mTOR） signaling pathway and autophagy in the kidney of diabetic nephropathy （DN） rats. MethodDN rat model was established through high-fat diet combined with intraperitoneal injection of streptozotocin （35 mg·kg-1）. DN rats were randomly assigned into model group， irbesartan （0.027 g·kg-1） group， low-dose HQS （0.54 g·kg-1） group and high-dose HQS （1.08 g·kg-1） group. The levels of 24 h urinary total protein （UTP）， serum albumin （Alb）， serum creatinine （SCr）， urea nitrogen （BUN）， triglyceride （TG） and total cholesterol （TC） were measured after 12 weeks of continuous administration. The pathological changes of renal tissue were observed via hematoxylin-eosin （HE） staining. The expression of podocyte split diaphragm proteins nephrin and podocin in the renal tissue were detected by immunohistochemistry. The protein levels and phosphorylation of key proteins in PI3K/Akt/mTOR signaling pathway， as well as the expression of yeast Atg6 homolog （Beclin1） and microtubule-associated protein 1 light chain 3 （LC3） in the renal tissue were analyzed by Western blot. ResultCompared with the control group， the model group showcased increased 24 h UTP， SCr， BUN， TG， and TC levels and decreased Alb level （P<0.01）. After modeling， the rats showed granulosity of epithelial cells of renal tubules， thickening of capillary basement membrane， proliferation of mesangial cells， and sclerosis of glomerulus. Furthermore， modeling down-regulated the expression of nephrin and podocin in the podocyte hiatus of glomerulus （P<0.01） as well as the protein levels of p-PI3K， p-Akt， and p-mTOR and the autophagy markers LC3 and Beclin1 in renal tissue （P<0.01）. Compared with model group， irbesartan and HQS decreased the 24 h UTP， Cr， BUN， TG， and TC levels， increased the Alb level， and alleviated the pathological damage of kidney. Moreover， they up-regulated the expression of Nephrin and Podocin in the podocyte hiatus of glomerulus， as well as the protein levels of p-PI3K， p-Akt， p-mTOR， LC3， and Beclin1 in renal tissue （P<0.05， P<0.01）. ConclusionHQS may inhibit the PI3K/Akt/mTOR signaling pathway to enhance podocyte autophagy and protect the glomerulus， thus slowing down the development of DN.