Abstract
Diabetic nephropathy (DN) is a major complication of type 1 diabetes mellitus, and hyperglycemia and hypertension are the main risk factors for the development of DN. N-Acetyl-Cysteine (NAC) has a variety of effects, interfering with the production and scavenging of free radicals and regulating the metabolic activity of tissue cells. However, the efficacy of NAC on DN treatment is unclear. Thus, this study investigated the protective mechanism of NAC combined with insulin on renal injury in dogs with DN. The forty dogs were selected and divided into control group, DM group, INS group, INS + NAC group and NAC group to establish the model for a trial period of 4 months. The results revealed that INS + NAC was effective in reducing and stabilizing blood glucose levels. Biochemical results showed that INS + NAC treatment significantly regulated the stability of UREA, CREA and fructosamine indicators. Meanwhile, histopathology staining showed significant glomerular wrinkling and fibrosis in the DM group, which could be reversed after INS + NAC treatment. In addition, INS + NAC could restore mitochondria homeostasis by upregulating the levels of mitochondrial fission (MFN1, MFN2 and OPA1) and inhibiting of mitochondrial fusion (DRP1, FIS1 and MFF) related indicators. Further studies revealed that INS + NAC regulated the expression levels of renal BNIP3, NIX and FUNDC1 in the DM group, thereby alleviating mitophagy. Collectively, these results suggested that NAC combined with insulin protects DN by regulating the mitochondrial dynamics and FUNDC1-mediated mitophagy.