石棉作业对工人血浆中谷胱甘肽S转移酶活性的影响

目的　探讨接触石棉是否会影响工人体内的谷胱甘肽S转移酶 (GST)活性及GSTM1基因型对体内GST活性的影响。方法　选择 94名石棉作业工人及 5 1名对照工人作为研究对象 ,通过问卷调查收集每人的一般情况和职业史等。采集静脉血分离血浆和淋巴细胞 ,血浆用于GST活性测定 ,淋巴细胞用于提取DNA进行GSTM1基因型分析。结果　石棉作业工人血浆中的GST活性 (2 3 0± 6 9)U/L ,明显低于对照组工人的 (32 6± 11 8)U/L ,且随着石棉作业工龄的延长及累积石棉接触剂量的增加 ,工人血浆中的GST活性呈逐渐下降的趋势。用GSTM1基因型对两组工人进行分层后发现 ,携带GSTM1+/ +和GSTM1- / -基因型的石棉作业工人 ,其血浆中的GST活性分别为 (2 4 0±6 1)U/L和 (2 2 5± 7 3)U/L ,均低于同种基因型的对照组工人 ,对照组分别为 (38 1± 13 2 )U/L和(2 6 8± 6 6 )U/L。同时还发现 ,携带GSTM1- / -的对照组工人血浆中的GST活性明显低于携带GSTM1+/ +者 ,而石棉作业工人组虽也有类似趋势 ,但差异无统计学意义。结论　接触石棉可明显降低体内GST的活性。在对照人群中 ,GST活性受GSTM1基因型的影响 ,而在石棉作业工人中 ,这种影响不明显。

Effects of exposure to asbestos on plasma activity of glutathione S-transferases

OBJECTIVE: To understand the effects of exposure to asbestos and GSTM1 genotypes on plasma activity of glutathione S-transferases (GSTs). METHODS: Ninety-four workers exposed to asbestos and 51 controls were selected, and their general information, occupational history and personal behavior were collected by questionnaire. Venous blood specimen was collected from each of them and plasma was separated for detection of GSTs activity and lymphocytes for DNA extraction and GSTM1 genotyping. RESULTS: Plasma activity of GSTs in the asbestos-exposed workers (23.0 +/- 6.9) U/L was significantly lower than that in the controls (32.6 +/- 11.8) U/L, which declined with the length of employment in asbestos industry and the increase of cumulated dose of asbestos. Stratification of workers by GSTM1 genotypes showed that plasma activity of GSTs in asbestos-exposed workers with GSTM1+/+ or GSTM1-/- were (24.0 +/- 6.1) and (22.5 +/- 7.3) U/L, respectively, lower than those in the controls with the same genotypes (38.1 +/- 13.2) and (26.8 +/- 6.6) U/L. Plasma activity of GSTs in the control workers with GSTM-/- was significantly lower than in those with GSTM+/+, and, so did in asbestos-exposed workers, but without statistically significant difference. CONCLUSION: Exposure to asbestos could significantly decrease plasma activity of GSTs, and GSTM1 genotypes could affect on the activity of GSTs in the control workers, which was not so obvious in asbestos-exposed workers.