Comparison between high fat diet and environmental pollutants exposure in the induction of adaptive mechanisms in rat liver mitochondria and endoplasmic reticulum

Chronic exposure to a high fat diet (HFD) and environmental pollutants can induce liver damage and steatosis often lead with oxidative stress generation and organelles dysfunction. Present work aims to compare the effect of HFD with that of environmental pollutant dichlorobiphenylethane (DDE) on oxidative stress, mitochondrial alterations, and endoplasmic reticulum (ER) stress in rat liver. The effect of simultaneous treatment with both HFD and DDE was also studied. Four groups of rats were treated for 4 weeks: ND and ND+DDE groups, treated with a standard diet (10.6% fats) associated or not with DDE (10 mg/Kg b.w.); HFD and HFD+DDE groups, treated with a HFD, (40% lard) associated or not with DDE (10 mg/Kg b.w.). Liver structure was studied by using Haemallume & Eosin. Oxidative stress was monitored spectrophotometrically. Protein markers of mitochondrial dynamics, ER-stress, autophagy, and inflammation were detected by Western blots. Caspase 3 activity and immunostaining were used as apoptotic index. HFD and DDE showed hepatic pro-oxidant effects. HFD induced lipid deposition, whereas DDE promoted parenchymal disorganization. Both HFD and DDE induced mitochondrial fragmentation, ER stress, inflammation, and apoptosis. Moreover, autophagy was found stimulated. Interestingly, HFD and DDE did not show cumulative effects. Concluding, HFD and DDE promote tissue alterations involving mitochondria and ER stress, thus representing a link between stressors exposure and liver injury.