The Effect Of Metformin On Induced Hepatocellular Carcinoma And The Change In VEGF、P53Expression In Experimental Rats

Objective:To observe the inhibitory effect of metformin on Diethylnitrosamine (DEN) and microcystin-LR (MC-LR)-induced liver cancer in rats, and its VEGF, P53expression, and to explore the anti-tumor effect and possible mechanism of metformin in liver cancer, and to provide a theoretical basis for further research and clinical application.Methods:Using DEN and MC-LR to establish the hepatocellular carcinoma model in rats:intraperitoneal injection of0.25%DEN (10mg/kg) and MC-LR (20ug/kg) every5days, altogether for16weeks, the fourth week of carcinogenesis when liver cell injury, the8-12th weeks when liver cells hyperplasia-hardening, the16th week when hepatocellular carcinoma. Sixty male Sprague-Dawley rats were randomly divided into control group, model group and metformin group (metformin orally250mg/Kg· d), Ten mice that randomly selected in three groups were sacrificed at12and16weeks. The Rats’livers were accurately weighed, recorded the number of liver nodules, and calculated liver weight/body weight ratio (liver index). Liver specimens were prepared for H.E.-stained, and immunohistochemistry. The protein expression of VEGF、P53was examined by immunohistochemistry. The VEGFmRNA level was examined by fluorescence quantitative PCR (FQ-PCR).Results:1. The rats of control group had good condition without abnormal mortality; the rats of model group appeared cirrhosis in the12th weeks and liver cancer in the16th weeks, the pathological changes of the metformin group were lighter compared with model group in the same period.2. The effect of metformin on weight, liver weight, liver index, liver nodules, number (16th week) in DEN+MC-LR-induced liver cancer:the liver index and the number of liver nodules of model group were all higher than the normal group rats (p<0.05), metformin group were lower than model group (p<0.05), but still higher than normal group.3. The effect of metformin on the expression of VEGF and P53on DEN+MC-LR-induced liver cancer:Immunohistochemistry showed that the VEGF、p53protein levels significantly higher than that of the control group (p<0.05), metformin group was lower than that model group (p <0.05). FQ-PCR showed that the VEGFmRNA of model group was significantly higher than the control group (p<0.05), metformin group’s was lower than that of the model group (p<0.05).Conclusion:1DEN+MC-LR is a feasible way to establish hepatocellular carcinomas model in rats2Metformin inhibits hepatocellular carcinoma induced by DEN+MC-LR in rats.3The expression level of VEGF and P53protein of liver tissue were significantly high in the HCC model induced by DEN+MC-LR, which can be suppressed by metformin. This experiment indicates that the anti-tumor effects of metformin in hepatocellular carcinoma may be related with VEGF and P53.