Abstract: BACKGROUND AND AIM: To explore the mechanism of toxic action as well as to provide basic data for prevention of dermatitis medicamentosa_like of trichloroethylene(DMLT). The changes of mitochondrial functions in keratinocytes after exposure to trichloroethylene and the protective effect of pre_treatment with ginkgo biloba extract (EGb) were performed. MATERIALS AND METHODS: Human keratinocytes were co_cultured with different concentrations of trichloroethylene for different times. To observe the protective effect of EGb, cells were pre_incubated with different concentrations of EGb for 2 hours, and then treated with 2.0 mmol/L TCE. MTT method was used to investigate cell viability and inhibition ratio of mitochondrial enzyme. ATPase activity was measured to indirectly find out the variation of mitochondrial energy production. Changes of mitochondrial membrane potential were assessed by flow cytometry(FCM) after dual_staining with rhodamine 123 and propidium iodide. RESULTS: Trichloroethylene decreased keratinocyte viability, ATPase activity and mitochondrial membrane potential while enhanced inhibition ratio of mitochondrial enzyme. Pre_treatment of EGb for 2 hours could dose_dependently attenuate the cytotoxicity of 2.0 mmol/L TCE, and the lowest effective protective dose of EGb was 10 mg/L(compared with 2.0 mmol/L TCE with no EGb pre_treatment,P<0.01). The mitochondrial functions in the human keratinocytes preincubated with 150 mg/L EGb prior to TCE could return to normal condition (compared with solvent control, P>0.05). CONCLUSION: Trichloroethylene induced changes of mitochondrial functions in keratinocytes through dose and time_dependent manner, and ginkgo biloba extract could protect mitochondria against functional damage.

Key words: trichloroethylene, keratinocytes, mitochondrial, ginkgo biloba extract