Sinomenine Hydrochloride Activates Podocyte Autophagy by Attenuating PI3K/AKT/mTOR Pathways to Protect Diabetic Nephropathy

Diabetic kidney disease (DKD) is a common complication of diabetes, often characterized by podocyte injury, proteinuria, and eventual renal failure. Sinomenine hydrochloride (SH), an active component derived from traditional Chinese medicine, is clinically effective in treating kidney diseases. This study investigates the protective effects of SH on podocytes under high-glucose conditions and its mechanism of action. Mouse podocytes (MPC-5) were treated with SH at concentrations of 50, 200, and 600 μg/mL under high-glucose conditions (30 mmol/L) for 24 h to establish a DKD model. Cell viability was assessed using CCK-8 assays, and apoptosis rates were measured using flow cytometry. Autophagy levels were evaluated by detecting LC3-II, Beclin-1, and P62 proteins via Western blot analysis, while the involvement of the PI3K/AKT/mTOR pathway was analyzed by examining phosphorylated AKT and mTOR. Transmission electron microscopy was employed to observe autophagosomes. SH improved podocyte viability, reduced apoptosis, and enhanced autophagic activity by increasing LC3-II and Beclin-1 expression while decreasing P62 levels. SH also downregulated p-AKT and p-mTOR, indicating inhibition of the PI3K/AKT/mTOR pathway. Electron microscopy confirmed increased autophagosomes in SH-treated groups. SH protects podocytes in a high-glucose environment by enhancing autophagy through inhibition of the PI3K/AKT/mTOR pathway. These findings provide insights into SH as a potential therapeutic agent for DKD management.