Qizhi Jiangtang capsule activates podocyte autophagy in diabetic kidney disease by inhibiting phosphatidylinositol 3-kinase/protein kinase B/mammalian target of rapamycin pathways.

Objective: To investigate the therapeutic action and mechanism of the Qizhi Jiangtang capsule (, QZJT) on diabetic kidney disease (DKD) treatment.

Methods: This experiment used db/db mice and podocytes (MPC5) to develop DKD model. Evaluation of the effect of the QZJT on db/db mice by testing urine and blood biochemical parameters (24-h urinary albumin, serum creatinine, blood urine nitrogen), pathological kidney injury, and podocyte integrity. Moreover, autophagosomes in podocytes of DKD mice and cultured podocytes were detected using electron microscopy. Additionally, Western blotting was applied to detect the expression of podocyte marker protein (podocin), autophagy-associated proteins, and phosphatidylinositol 3-kinase/protein kinase B/mammalian target of rapamycin (PI3K/AKT/mTOR) signaling pathway changes and .

Results: QZJT significantly reduced urine protein, blood nitrogen urea, and serum creatinine and showed histological restoration of renal tissues. QZJT also significantly improved the down-regulation of podocin and foot fusion and effacement in db/db mice. QZJT increased autophagic vesicles in mice and cultured podocytes. QZJT also upregulated microtubule-associated protein 1 light chain 3-II (LC3-II) / (LC3-I) and Beclin-1 and downregulated phosphorylated-PI3K (p-PI3K), p-AKT, and p-mTOR in db/db mice and MPC5 cells. However, autophagy inhibitor 3-methyladenine partially alleviated the above effects in MPC5 cells.

Conclusions: These results showed that the QZJT can enhance podocyte autophagy and ameliorate podocyte injury in DKD by inhibiting the PI3K/AKT/mTOR signaling pathway.