Effects Of Cyclooxygenase-2 Inhibitors On Cellular Senescence And Expression Of P53 And P21 Gene In Steatotie Hepatoeytes

Objective: To explore the impact of COX-2 inhibitors on cellular senescence and its related mechanism in steatotie hepatoeytes.Methods:At first this study used SD rats as the research object. the SD rats were randomly divided into normal control group(group A), non-alcoholic fatty liver disease(NAFLD) group(group B) and NAFLD+ nimesulide group(group C). After corresponding processing, collecting rats venous blood to test serum triglyceride(TG), total cholesterol(TC), alanine aminotransferase(ALT) and aspartate transaminase(AST). To make pathological slices of rat liver tissue, HE staining observed pathology change in rat liver tissue. Beta galactose glucoside enzyme staining detected cellular senescences in rat liver tissue. Based on animal experiments, human hepatocyte strain LO2 cells as the research object and oleic acid as inducers, to establish an in vitro hepatic steatosis cell model. MTT, oil red O staining and intracellular TG detection selected the optimum condition of establishing hepatic steatosis cell model. On the basis of the hepatic steatosis LO2 cell model LO2 cells were divided into normal control group(group A), hepatocyte steatosis model group(group B), hepatocyte steatosis model + nimesulide group(group C). After corresponding processing, each group cells made beta galactose glucoside enzyme staining to detect cellular senescences. Real-time quantitative PCR detected the expression of p53 and p21 genes.Results:Animal experiment1.Results of serum triglyceride(TG), total cholesterol(TC), alanine aminotransferase(ALT), aspartate transaminase(AST) and HE staining showd, compared with group A, in group B steatosis and tissue inflammation were increased significantly(P< 0.05). Compared with group B, in group C steatosis and tissue inflammation were significantly decreased(P< 0.05).2.Results of beta galactose glucoside enzyme staining showd, compared with group A, in group B cellular senescence index was significantly decreased(P< 0.01). Compared with group B, in group C cellular senescence index of the liver tissue was increased significantly(P< 0.01).Cell experiment1.Results of MTT, oil red O staining and intracellular TG detection showed that LO2 cells within 20?g/ml oleic acid for 72 h to establish hepatic steatosis cell model work best.2.Results of beta galactose glucoside enzyme staining showd, compared with group A, in group B and group C cellular senescence were increased significantly(P< 0.01). Compared with group B, in group C cellular senescence was increased significantly(P< 0.01).3.Results of real-time quantitative PCR showd, compared with group A, in group B expressions of p53 and p21 gene were up-regulated. The expression of p53 gene had significantly difference(P< 0.05). Compared with group B, in group C expressions of p53 and p21 gene were up-regulated significantly(P< 0.01).Conclusion:1.COX-2 inhibitors nimesulide could promote cellular senescence in hepatic steatosis cell.2.COX-2 inhibitors nimesulide may upregulate the expressions of p53 and p21 gene to promote cellular senescence in hepatic steatosis cell.