Abstract: OBJECTIVE: The in vitro CHO-K1 cells HGPRT gene mutation test and the mouse bone marrow micronucleus test were used to analysis the expression of genetic toxicity of a pesticide,Paichongding. METHODS: In CHO-K1 cells,the positive medium and different concentrations of Paichongding were added into the culture medium (+S9/-S9). After treatment of the cells at low density,mutant selection and colony formation were calculated at the same time with cell survival rates. The 2×10⁵/dish was inoculated with 6-TG,at the same time,the other by the 200/plate were calculated after 7 d,colony number,survival rate and mutation frequency. Mouse bone marrow cell micronucleus test were conducted with high,medium and low Paichongding dose groups,positive control group and negative control group. Femoral bone marrow smears were observed:1 000 polychromatic erythrocytes micronucleus in polychromatic cells and 200 polychromatic erythrocytes (PCE) and the number of mature red blood cells (NCE),red blood cell count percentage calculation PCE. RESULTS: Compared with the control group,the highest dose of Paichongding significantly reduced the relative survival rate of CHO-K1 cells. Paichongding cell gene mutation frequency in each dose group had no significant difference (P > 0.05) while the positive control group (cell gene mutation frequency) had significant difference (P < 0.01). From the Paichongding treated mice,the immature red blood cells accounted for the proportion of the total number of red blood cells was not less than 20% of the negative control group. Compared with the negative control group,there was significant difference between male and female mice in positive control group (P < 0.01),while there was no significant difference in the micronucleus rate of male and female mice in each dose group (P > 0.05). CONCLUSION: Under the experimental conditions,no genetic toxicity was found with Paichongding。

Key words: Paichongding, genetic toxicity, HGPRT gene mutation test, micronucleus test