Objective: To observe the pathological changes and investigate the correlation of hepatocyte apoptosis with cytochrome P450 2E1(CYP2E1) expression and oxygen free radical in alcoholic liver disease (ALD) in rat.
Methods: 40% ethanol in the dose of 8 g/kg body weight was given to rats by gavage twice daily for 8 weeks in model group (n=37), and rats in control group (n=33) received same volume of saline by gavage. At the end of the 8th week, the contents of serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were determined. The pathological changes in the liver was observed under light microscope with hematoxylin and eosin (HE) staining, and hepatocyte apoptosis was detected by the terminal deoxynucleotidyl transferase mediated dUTP biotin nick and labeling (TUNEL) method. Expression of serum CYP2E1 was determined by polymerase chain reaction (PCR), the contents of malondialdehyde (MDA) and activities of superoxide dismutase (SOD) in serum were detected by thibabituric acid (TBA) quantifying method.
Results: The TUNEL positive cells were located around the central vein, and spotty and focal necrosis was found in the ALD group. The apoptotic index (AI) in the ALD group was significantly higher than in the control group (P<0.05). To express in CYP2E1, the allelic frequency of c1 and c2 were 91.65%, and 8.35% respectively, in control group, while the allelic frequency of c1 and c2 were 53.35% and 46.65%, respectively, in ALD group, and there were significantly differences between two groups (all P<0.05). The content of MDA in serum had positive correlation with hepatocyte apoptosis index (MDA vs. AI, r( MDA ) =0.644), and the activity of SOD in serum had negative correlation with AI (SOD vs. AI, r( SOD ) =-0.511, all P<0.05) in the ALD group, and there was negative correlation between MDA and SOD (r=-0.582, P<0.05).
Conclusion: Chronic alcohol administration induced alcoholic liver disease and liver dysfunction, and hepatocyte apoptosis is enhanced. Rsa I and Pst I RFLPs are related with ALD in model rats, and c2 gene might be related with the development of ALD. The content of MDA and activity of SOD play an important role in the process of hepatocyte apoptosis and lipid peroxidation process.