漢方方剤柴朴湯によるメチルコラントレン誘発肉腫の発症抑制に関する研究

The present study investigated the preventive effect of Saiboku-to, a Chinese herbal medicine, upon chemically induced carinogenesis in mice, and analyzed the mechanism of effect. Saiboku-to was orally administered to C3H/HeJ mice in a daily dose of 100mg/kg or 1000mg/kg in each of two groups. Six weeks after initiating Saiboku-to administration, mice were subcutaneously injected with a tumorigenic dose (1mg/mouse) of 3-methylcholanthrene (MC) and tumor development was observed for 25 weeks. In control mice, the incidence of tumor was 40% 10 weeks after MC injection. However, the tumor incidence in Saiboku-to treated mice was only a few percent 10 weeks after MC injection. A tumor incidence of 40% in Saiboku-to treated mice was reached about 18 weeks after MC injection, showing the delaying effect of Saiboku-to on carcinognesis. Therefore, a delaying effect on carcinogenesis was observed in Saiboku-to treated mice, although all mice had tumors within 23 weeks after MC injection. The mechanism of the delay in carcinogenesis was investigated by depletion of NK cells, T cells and macrophages in vivo, respectively. The delay of carcinogenesis disappeared after using anti-asialo-GM1 antibody, anti-thymocyte antibody, and carrageenan in Saiboku-to treated mice, showing that NK cells, T cells, and macrophages play an important role in delaying by Saiboku-to administration in experimental carcinogenesis. Moreover, prior treatment for 6 weeks with Saiboku-to significantly enhanced the NK cell activity of splenic cells and the cytotoxity and lysosomal enzyme activities (acid Phosphatase, beta-galactosidase) of peritoneal macrophages in normal mice. These augmentations were suppressed using anti-asialo GM1 antibody or carrageenan in vivo. Thus, Saiboku-to showed prophylactic effect on chemical carcinogenesis, suggesting activa-tion of the immune status of the host.

原著