Abstract: OBJECTIVE: To study mRNA expression of apoptosis genes Bcl_2, BAX, BAD in spleen and peripheral blood of guinea pigs after treatment with trichloroethylene (TCE). METHODS: Guinea pig maximization test (GPMT) was applied in this study, 18 guinea pigs were randomly divided into 3 groups, namely negative control, positive control and TCE treatment. Animals of the 3 groups were treated with olive oil, 2,4_dinitrochlorobenzene (DNCB), and TCE, respectively, by intradermal injection. Spleens and peripheral blood were collected from the animals for mRNA expression assay, Bcl_2, BAX, BAD in lymphocytes of spleen and peripheral blood were measured by real_time fluorescent PCR assay. RESULTS: Obvious skin damage was observed in the groups of positive control and TCE treatment, the skin damage included erythema and edema. The levels of Bcl_2, BAX and BAD mRNA expression increased significantly in spleen lymphocytes in positive control and TCE treatment groups. However, the levels of Bcl_2, BAX and BAD mRNA did not elevate significantly in peripheral blood lymphocytes in positive control and TCE treatment groups, when compared with negative control. CONCLUSION: Trichloroethylene could induce skin allergic reaction in guinea pigs，it also had effects on mRNA expressions of Bcl_2, BAX, BAD in spleen lymphocytes of guinea pigs.

Key words: trichloroethylene, guinea pig, spleen, peripheral blood, lymphocytes, apoptosis gene