Yiqi Qingre Xiaozheng formula protects against diabetic nephropathy by restoring autophagy in mice

Objective: To evaluate the protective effect of Yiqi Qingre Xiaozheng formula (YQQRXZF) via the regulation of autophagy in diabetic nephropathy (DN) mice induced by injection of streptozotocin (STZ) after high fat diet (HFD). Methods: The composition of YQQRXZF was analyzed by high performance liquid chromatography-electrospray ionization/mass spectrometry (HPLC-ESI/MSn). The DN model was induced by intraperitoneally injection of 50 mg/kg STZ within 5 days, followed by HFD feeding for 8 weeks in C57BL/6J mice. Mice were randomly separated into DN group, YQQRXZF group, irbesartan group, and control group. Blood glucose was calculated, and body weight was measured every 2 weeks. An enzyme-linked immunosorbent assay was used to measure the urinary albumin-to-creatinine ratio (uACR) before and after treatment, and the serum concentrations of total cholesterol (TC), low-density lipoprotein (LDL), triglycerides (TG), high-density lipoprotein (HDL), blood urea nitrogen (BUN), and serum creatinine (Scr) were measured. In addition, hematoxylin-eosin (H&E) staining, periodic acid-Schiff (PAS) staining, Masson's trichrome staining, and transmission electron microscopy (TEM) were used to observe pathological changes in renal tissue. Autophagy levels were determined by immunofluorescence staining. Results: In this study, 21 dominant chemical constituents were identified in YQQRXZF. The treatment group reduced uACR in a more significant way than the DN group (P = .018). The treatment group reduced TC, TG, and LDL concentrations after YQQRXFF treatment (P = .021, P = .014 and P = .026, respectively). H&E, PAS, and Masson staining showed that pathological damage to mice kidneys improved, the volume of renal glomeruli was reduced, and glomerular sclerosis and fibrosis were reduced. Immunofluorescence analysis revealed that expressions of LC3-Ⅱprotein increased in the treatment group (P = .013). In contrast, the protein expressions of P62 were reduced after treatment (P = .025). Conclusion: YQQRXZF effectively attenuates kidney injury in DN mice, probably by regulating autophagy.