RESUMO
Changes in lifestyle and food habits increase the prevalence of nonalcoholic fatty liver disease [NAFLD]. It is a chronic condition that has no or few symptoms. It may be accompanied by inflammation and insulin resistance. Moreover, it is closely linked to diabetes. Metformin is an antidiabetic agent that can improve insulin resistance. The study was conducted to investigate the effect of metformin on liver injury induced by a high-fat diet. The study lasted for 12 weeks. Thirty-six adult male albino rats were used and divided into four groups. Group I was the control group. Group II rats received metformin. Group III rats were fed a high-fat diet for induction of NAFLD. Group IV rats were fed a high-fat diet for induction of NAFLD and then administered metformin orally in the last 4 weeks of the study. Liver specimens were processed for light and electron microscopic examination. Moreover, liver weight index was determined, and biochemical, morphometric, and statistical studies were performed. Induction of NAFLD [group III] resulted in severe insulin resistance. Hepatocytes showed macrovesicular and microvesicular steatosis, ballooning, and lobular inflammation. The number of positive cells and the reaction for tumor necrosis factor-alpha in group III apparently increased as compared with group IV. Lipid droplets, loss of mitochondrial cristae, and dispersion of rER were detected in group III. Metformin improved insulin resistance, and liver histological changes were fewer than those in group III. Metformin can greatly improve liver histological changes associated with a model of NAFLD