Apoptosis and bcl-2 protein expression in experimental alcoholic liver disease in the rat

We used the intragastric feeding rat model to investigate the relationship between severity of alcoholic liver injury, apoptosis, bcl-2 protein expression, and lipid peroxidation. Rats were fed ethanol with different dietary fats (saturated fat, corn oil, and fish oil) for a 1-month period. Apoptosis was evaluated using an immunohistochemical method, and flow cytometry. Bcl-2 protein concentrations in liver were evaluated by Western blot analysis and lipid peroxidation by measurement of conjugated dienes. Pathological changes (fatty liver, necrosis, and inflammation) were present in corn oil-ethanol and fish oil-ethanol groups only. The highest number of apoptotic cells were seen in the group of rats exhibiting liver injury. The fish oil-ethanol-fed group had the highest concentrations of bcl-2 protein; this protein was localized in the bile duct epithelial and inflammatory cells. A significant correlation was seen between bcl-2 protein assessed densitometrically and the number of inflammatory cells/mm2 (r = 0.78, p < 0.02) and conjugated diene levels (r = 0.82, p < 0.01). Increased numbers of apoptotic cells were seen in rats developing ethanol-induced pathological liver injury. Increased bcl-2 protein concentration are associated with the presence of inflammatory cells and lipid peroxidation.