Tangningtongluo Tablet ameliorates pancreatic damage in diabetic mice by inducing autophagy and inhibiting the PI3K/Akt/mTOR signaling pathway

Background: Diabetes is a metabolic disease characterized by hyperglycaemia. Tangningtongluo Tablet (TNTL) is an inpatient formula extensively utilized to treat diabetes mellitus (DM), but the protective mechanism is not clear. This study aimed to investigate the relevant mechanisms by which TNTL affects pancreatic damage in diabetic mice and autophagy. Methods: The impact of TNTL on pancreatic damage in diabetic mice in vitro and in vivo was investigated via glucose and lipid metabolism analyses, HE staining, CCK-8, TUNEL staining, Annexin V/PI, and Western blotting. Molecular docking and Western blotting were used to verify the results of network pharmacological analysis, which was carried out to explore the mechanism by which TNTL affects DM. The autophagosome levels were visualized via RFP-GFP-LC3 and transmission electron microscopy, and lysosomal function was evaluated via Lysotracker red staining. Western blot, immunohistochemistry and immunofluorescence staining were used to detect the expression of the autophagy proteins LC3, p62 and LAMP2. Results: Compared with the model group, TNTL protected pancreas from oxidative stress, decreased the level of MDA, increased the levels of SOD and GSH-px, induced the occurrence of autophagy and decreased the levels of apoptotic factors. Moreover, TNTL inhibited the protein expression of p-PI3K, p-Akt and p-mTOR, increased the levels of LC3 and LAMP2 and decreased the level of p62, and the autophagy inhibitor CQ blocked the protective effect of TNTL on pancreatic damage in diabetic mice. Conclusion: These results demonstrated that TNTL ameliorated pancreatic damage in diabetic mice by inhibiting the PI3K/Akt/mTOR signaling and regulating autophagy.