Stichopus Japonicus Acid Mucopolysaccharide Inhibition Of Tumor Formation On Den-induced Liver Cancer In Rats

Objective:To observe Stichopus japonicus acid mucopolysaccharide (SJAMP) on DEN-induced rat liver cancer during the formation of the inhibitory effect on tumor by immunohistochemistry, PCR, western-blot and other methods to provide the basis for the application of SJAMP.Methods:Model of rats liver cancer was established, wistar rats were randomly divided into five groups.Each group included ten rats. Normal control group(A), model group(B),SJAMP groups:low dose group (C,1/5mg/kg), the middle dose group (D,35mg/kg), high dose group (E,70mg/kg). SJAMP groups fed different doses of SJAMP, while in the establishment of liver cancer model. After fed16weeks, rats were killed. During the experiment,we compared the incidence of liver cancer, and observe the changes in the tumor tissue and cells of rats in each group in the fluorescence microscopy and electron microscopy, immunohistochemical method to detect cancer cells, the expression of PCNA, p53, p21, MDM2, the expression of cyclinD1and CDK4expression by RT-PCR method, Western blot detection of pRb and of E2F-1.Results:Except one rat in high-dose group, the remaining rats in other groups developed liver cancer.The model group rats had the most number of tumber nodules while high-dose group rats had the least number of tumor nodules. The tumor volume of SJAMP groups were significantly less than the model group (F=16.53, q=5.23～9.60, P<0.05). SJAMP high dose group tumor volume was significantly less than SJAMP low-dose group (q=4.56, P<0.05). Electron microscopy, in SJAMP groups had amounts of apoptotic bodies in rat hepatocytes. Immunohistochemical results showed that compared with the model group, other groups the expression of PCNA decreased, the differences were significant (F=60.23, q=6.27-20.57, P<0.05);the expression of P53decreased, the differences were significant (F=63.29, q=4.83-20.47, P<0.05); the expressionof MDM2decredsed, the differences were significant (F=43.22, q=7.25-10.56, P<0.05);the expression of P21increased, the differences were significant (F=47.22, q=5.30-15.60, P<0.05). RT-PCR results showed that compared with the model group, the other groups cyclinD1expression decreased,the differences were significant (F=49.91, q=5.94～18.52, P<0.05); CDK4expression decreased, the differences were significant (F=50.21, q=5.72～18.08, P<0.05). Western Blot results showed that compared with the model group,other groups pRb expression increased, the differences were significant (F=63.25, q=3.56-16.36, P<0.05); E2F-1expression decreased, the differences were significant (F=268.10, q=14.55-35.45, P<0.05).Conclusion:Suchopus japonicus acid mucopolysaccharide can inhibit the formation of liver cancer induced by DEN. SJAMP possibly through inhibite PCNA、p53、MDM2expression, promote the expression of P2、pRb. SJAMP can inhibite the expression of CyclinD1、CDK4and E2F-1to inhibit tumor cell proliferation and induce abnormal proliferate cell apoptpsis.