In-vivo evaluation of Mediterranean diet effects in a db/db mouse model of type 2 diabetes: a focus on liver

Dietary interventions can slow-down chronic and degenerative diseases as type 2 diabetes (T2D) and related co-morbidities, among which fatty liver. The Mediterranean diet (MD) has received particular attention for its antiobesity, antioxidant, and anti-inflammatory properties, however, an unambiguous biochemical characterization of its protective effects is still missing. The aim of this study was to decipher the putative organ protection effects of an experimental MD cocktail in a mouse model of human T2D, the db/db mouse affected by hyperphagia, obesity, hyperlipidemia, hyperinsulinemia, insulin resistance and diabetes, pinpointing the effects on the liver. Db/m (control) and db/db mice were fed with either a standard diet (db/db SD), or a western diet (db/db WD) or a MD (db/db MD) for 8 weeks. During the treatments, animals were monitored weekly for body weight, food, and water consumption; monthly for blood glucose, insulinemia, inflammatory markers, transaminases, triglycerides, and LDL cholesterol. After the sacrifice, markers of hepatic damage, oxidative stress and mitochondrial functionality were evaluated. The key results showed that in liver the MD cocktail affected triglyceride and lipid peroxide accumulation, ROS production, and protein expression levels of markers of antioxidant capacity, mitochondrial biogenesis and mitophagy. Although prevention can be excluded, the MD cocktail exerts protective effects on liver of db/db overweight and diabetic mice by modulating at the cellular level molecular pathways related to the chemical composition of the cocktail and to its high antioxidant power. These results open new perspectives for the nutritional approach in the management of T2D patients.