中文摘要：

目的观察三氯乙烯（TCE）致人原代角质形成细胞（KC）损伤过程中caspase-8、caspase-9活力及细胞凋亡率的变化，探讨TCE引起KC凋亡的可能机制。方法体外培养的KC分别给予0．125、0．250、0．500、1．000和2．000mmol／L的TCE染毒4、8、12、24h，以100μmol／L的caspase-9特异抑制剂Z—LEHD—FMK预处理细胞1h，再用2．000mmol／LTCE染毒12h，MTT法检测细胞活力变化，分光光度法检测caspase-8及caspase-9活力变化，流式细胞仪检测细胞凋亡率变化。结果与空白对照相比，2．000和1．000mmol／LTCE染毒组作用8h后细胞活力降低，染毒超过12h，各剂量组细胞活力均降低，差异有统计学意义（P〈0．05或P〈0．01）。在不同的时间段，各剂量组的caspase-8活力与对照组比较，差异无统计学意义（P〉0．05）。染毒8h时，2．000mmol／LTCE组caspase-9活力明显高于对照组，差异有统计学意义（P〈0．05）；12和24h时，各剂量组caspase-9活力与对照组比较，差异均有统计学意义（P〈0．05或P〈0．01）。不同剂量的TCE染毒12h后，2．000mmol／LTCE染毒组细胞凋亡率升高至（80．43±4．21）％，空白对照组为（9．40±2．98）％，除0．125mmol／LTCE组外，其他各染毒组的细胞凋亡率与对照组相比，差异均有统计学意义（P〈0．05），剂量一效应关系明显。Caspase-9抑制剂预处理组caspase-9活力及细胞凋产率较2．000mmol／LTCE染毒组明显降低，差异有统计学意义（P〈0．01）。结论Caspase-9的活化在TCE诱导的体外培养的人KC的凋亡过程中发挥重要作用。

英文摘要：

Objective To observe the change of caspase-8,easpase-9 activity and apoptosis rates in the process of trichloroethylene-indueed damage in keratinocytes,and explore the tentative mechanism of apoptosis. Methods Human keratinoeytes were exposed to 0.125,0.250,0.500,1.000 and 2.000 mmol/L triehloroethylene for 4,8,12 and 24 h. The inhibitive groups were pretreated with 100 μmol/L Z-LEHD-FMK （a specific inhibitor of caspase-9） for 1 h,and were stimulated with 2.000 mmol/1 TCE for 12 h. MTT assay was used to detect the viability of different cells;The activity of easpase were calculated according to spectrophotometry;Change of the apoptotic rates was assessed by flow eytometer （FCM） after double-stained with Annexin V-FITC and propidium iodide（PI）. Results （ 1 ）The minimum effective concentration for cell viability reduction was 0. 125 mmol/L at 12 h and the shortest time required to produce a change was 4 h at a concentration of 2.000 mmol/L （compared with control group,P〈0.01 ）. Cell viability in all the groups markedly decreased from 12 h to 24 h （P〈0.05）. （2）The activity of caspase-8 in the various dosage groups at different times had no statistical difference compared with the control group, P〉0.01. （3）At 8 h, 1.000 and 2.000retool/ L TCE groups could significantly enhance caspase-9 activity（P〈0.05 ）. The easpase-9 activity in all the groups showed differences and was significantly higher than those of control cells when time was over 12 h （P〈0.05）. （4）After exposing to different dosages of TCE for 12 h,the rate of apoptosis rose to （80.43±4.21）% with the increase of dosage,compared with the control group, （9.40±2.98）%,which showed a dose-effect relationship. （5）The cells pre-treated with easpase-9 inhibitor resuhed in a decrease in the caspase-9 activity and apoptosis rates （compared with 2.000 mmol/L TCE exposed group,P〈0.01 ）. However,there was no statistical significance in comparison with the control group （P〉0.05）. Conclusion C