[Preliminary study on biological behavior and staging of transplanted hepatoma in rats]

Effects of Agaricus brasiliensis mushroom in Walker-256 tumor-bearing rats

Agaricus brasiliensis is a mushroom native to São Paulo State, Brazil, that is studied for its medicinal proprieties. This work aimed to investigate the antitumoral activity of A. brasiliensis extracts and pure powdered basidiocarp preparation using Walker-256 (W256) tumor-bearing rats, a model for cancer-related cachexia studies. The rats were treated for 14 days by gavage (136 mg/kg) and at the end of the experiment tumors were collected to calculate mass and volume. Blood was collected for determination of plasma glucose, albumin, alanine aminotransferase (ALT), and aspartate aminotransferase (AST). Hepatic and tumor enzymes indicating oxidative stress were also evaluated. The results showed that all 4 treatments (pure powdered basidiocarp and aqueous, acid, and alkaline extracts) significantly reduced tumor size and promoted gain in body weight. Plasmatic analysis showed a reduction in AST level and increased glycemia in the treated rats. Pure basidiocarp preparations improved the liver catalase and superoxide dismutase activity, but did not change the glutathione S-transferase activity. The data collected from the W256 tumor-bearing rats revealed the beneficial effects of A. brasiliensis in tumor treatment, mainly related to cachexia. The benefits can be partly related to antioxidant activity and to reduction of weight loss and tumor growth.

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

OBJECTIVE

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.

METHODS

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.

RESULTS

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.

CONCLUSION

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.