Abstract: ObjectiveTo observe the changes of p38 mitogen-activated protein kinase (p38MAPK) and nuclear factor-κ Bp 50 (NF-κBp50) in carbon tetrachloride (CCl₄) induced liver fibrosis and to explore their effects on hepatic fibrosis. MethodsThirty Sprague-Dawley rats were randomly divided into normal control group,4 weeks liver fibrosis group and 8 weeks liver fibrosis group.Liver fibrosis model was induced by hypodermic injection of 40% CCl₄ at the dosage of 0.3 ml/100 g body weight.The levels of malondialdehyde (MDA) and superoxide dismutase (SOD) in liver tissue were measured with colormtric method and the expressions of p38MAPK and NF-κBp50 protein were detected with immunohistochemical techniques and western blot. ResultsCompared with the normal control group,the levels of p38MAPK(7.9±2.3),NF-κBp50(16.3±8.1),and MDA(1.8±0.9 nmol/mgprot) in 4 weeks liver fibrosis group and the levels of p38MAPK(11.5±6.8),NF-κBp50(24.6±13.5),and MDA(2.9±1.3 nmol/mgprot) in 8 weeks liver fibrosis group were increased,while the activityies of SOD (40.6±5.8,34.4±3.1 u/mgprot) in 4 weeks and 8 weeks liver fibrosis groups were decreased. Conclusionp38MAPK,NF-κBp50 and oxidative stress may play important roles in CCl₄ induced liver fibrosis.