Experimental study on the glucagon-likepeptide 1 receptor agonist modulation of insulin resistance and hepatic oxidative stress in rats with diabetes mellitus combined with nonalcoholic fatty liver disease

Abstract

To study the effect of glucagon-likepeptide 1(GLP-1)receptor agonist on insulin resistance and hepatic oxidative stress in rats with diabetes mellitus combined with nonalcoholic fatty liver disease. 36 male SD rats were served as the experimental animal and randomly divided into control group, model group, and GLP-1 group. The rats of control group were given routine diet with intraperitoneal injection of normal saline, those in model group were given high fat diet and intraperitoneal injection of normal saline, while GLP-1 group rats were fed with high fat diet and intraperitoneal injection of liraglutide. After 4 weeks of treatment, insulin resistance, lipid metabolism, liver injury and oxidative stress were all assessed. Serum fasting blood glucose, fasting insulin, total cholesterol, triglyceride, alanine transaminase(ALT), aspartate transaminase(AST)levels and total cholesterol, triglyceride contents in liver tissue, and as well as homeostasis model assessment for insulin resistance(HOMA-IR)levels of model group were significantly higher than those of control group, complex insulin sensitivity index(ISIcomp)level was significantly lower than that of control group; serum fasting blood glucose, fasting insulin, total cholesterol, triglyceride, ALT, AST contents and HOMA-IR levels of GLP-1 group were significantly lower than those of model group, ISIcomp level was significantly higher than that of model group; superoxide dismutase(SOD), glutathione peroxidase(GSH-Px), catalase(CAT)contents in liver tissue of model group were significantly lower, while malondialdehyde content and SOD, GSH-Px, CAT, NF-E2 related factor-2(Nrf-2), antioxidant response element(ARE), heme oxygenase-1(HO-1), quinone oxidoreductase-1(NQO-1), glutathione thiol transferase(GST)mRNA expression were significantly higher than control group; SOD, GSH-Px, CAT contents and SOD, GSH-Px, CAT, Nrf-2, ARE, HO-1, NQO-1, GST mRNA expression in the liver tissue of GLP-1 group were significantly higher, while malondialdehyde content was significantly lower than that of model group. GLP-1 receptor agonist reduces insulin resistance and liver oxidative stress injury in diabetic rats with nonalcoholic liver disease. (Chin J Endocrinol Metab, 2017, 33: 228-232) Key words: Diabetes mellitus, type 2; Nonalcoholic fatty liver disease; Glucagon like peptide -1; Insulin resistance; Oxidative stress