Inhibition action of bufalin on human transplanted hepatocellular tumor and its effects on expressions of Bcl-2 and Bax proteins in nude mice

Abstract

To investigate the anti-tumor effect of bufalin and its regulation on Bcl-2 and Bax proteins in orthotopically transplanted tumor of human hepatocellular carcinoma in nude mice. Orthotopically transplanted tumor of human hepatocellular carcinoma was established in nude mice. The mice were randomly divided into five groups: high-dose bufalin-treated group (1.5 mg/kg), medium-dose bufalin-treated group (1 mg/kg), low-dose bufalin-treated group (0.5 mg/kg), adriamycin-treated group (8.0 mg/kg), and normal saline-treated group. After 25 days, mice were sacrificed. The tumor volume was measured, and the pathological changes of tumor tissues were detected by HE staining to observe the tumor necrosis degree. Cell morphological changes were also observed by an electron microscopy. Label index of tumor cell apoptosis was assessed by terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL), and the expressions of Bcl-2 and Bax proteins were determined by immunohistochemical method. The tumor volume in the bufalin-treated groups was shrunk significantly compared with that in the normal saline-treated group (P<0.01). The survival time of the bufalin-treated groups was prolonged compared with that of the adriamycin-treated group and the normal saline-treated group P<0.05. Apoptotic characteristics could be seen in tumor tissues of the bufalin-treated groups. The label index of tumor cell apoptosis in the bufalin-treated groups (5.87+/-2.13, 8.86+/-2.96 and 10.60+/-3.42 in low-, medium- and high-dose groups respectively) was higher than that in the adriamycin-treated group (3.28+/-0.98) (P<0.05, P<0.01). The expression of Bax was up-regulated, while no changes were detected as to Bcl-2 protein in tumors of the bufalin-treated groups. Bufalin has significant anti-tumor effect on the orthotopically transplanted tumor of human hepatocellular carcinoma in nude mice. Its effect might be related to up-regulation of Bax protein and inducement of the tumor cell apoptosis.