OBJECTIVETo investigate the inhibitory effect of Oridonin injection on heterotransplanted tumors of human gastric adenocarcinoma cell line BGC823 cells in nude mice and explore its mechanism.

METHODSHeterotransplanted models of human gastric adenocarcinoma cell line BGC823 cells in nude mice were established. They were divided at random into three groups as control group, low-dose group and high-dose group. The Oridonin solution at concentration of 37.5 mg x kg(-1 x d(-1) and 75 mg x kg(-1) x d(-1) were injected to the mice in low-dose group and high-dose group, respectively, and 0.9% sodium chloride was injected to the mice of control group per day for 10 days sequentially. The mice of the three groups were sacrificed at 11th day after the first injection of Oridonin. The tumor weight of the sacrificed mice was measured. Morphological and ultrastructural examinations of the tumors were carried out by light and electron microscopy. The expression of bcl-2, Bax, Fas and FasL was detected by immunohistochemistry.

RESULTSOridonin injection showed a suppressive effect on the growth of heterotransplanted tumors in the nude mice. The tumor growth inhibition rates were 48.5% and 70.7% in the low-dose and high-dose groups, respectively. The morphological study demonstrated that tumor cells displayed a typical appearance of apoptosis. The expression of bcl-2 was down-regulated, while Bax, Fas and FasL were up-regulated.

CONCLUSIONOridonin can markedly inhibit the growth of heterotransplanted human gastric adenocarcinoma in nude mice. It was due, at least in part, to the induction of apoptosis in cancer cells.