XRCC3基因多态性与铅作业男工铅毒性易感性的关联研究

Relationship between XRCC3 gene polymorphism and susceptibility m lead poisoning in male lead-exposed workers

目的研究x射线交错互补修复基因3（XRCC3）多态性与铅作业男工铅毒性易感性的关系。方法采集某蓄电池企业326名铅作业男工外周静脉血和晨尿样品，检测血铅、尿铅、血锌原卟啉（zPP）、血钙和血铁等指标，采用聚合酶链式反应限制性片段长度多态性分析技术（PCR．RFLP）检测XRCC3基因型，分析铅作业男工不同基因型与铅毒性易感性的关系。结果326名铅作业男工XRCC3基因分布呈现多态现象，各基因型（野生型XRCC3．241CC、杂合突变型XRCC3．241CT、纯合突变型XRCC3．2411Tr）的分布频率符合遗传学的Hardy—Weinberg平衡定律（P〉0．05）；不同基因型组（野生型XRCC3-241CC与突变型XRCC3—241CT/TT）工人尿铅、zPP、血钙、血铁水平比较的差异无统计学意义（P〉0．05）；XRCC3．241CT／Tr基因型组工人血铅水平平均值高于XRCC3—241CC基因型组，差异有统计学意义（P〈0．05）；以血铅水平1．90μmol／L为界，经X^2检验、logistic回归分析显示，高铅组XRCC3．241CT／Tr基因型的比例大于低铅组，差异有统计学意义（P〈0．05），XRCC3．241CT／TF基因型组工人较XRCC3．241CC基因型组工人高血铅发生率的风险明显增高（OR=2．34，95％CI=1．61～5．13）；多元线性回归显示，XRCC3．241CT／Tr基因型工人血铅水平高（β=0．116，P〈0．05）、有吸烟习惯工人铅吸收明显（／3=0．188，P〈0．05），良好个体防护可以减少铅吸收（β=0．247，P〈0．05）、血清Ca2＋低的个体的血铅水平高（β=-0．145，P〈0．05）。结论在相同职业铅暴露环境下，XRCC3．241CT／Tr基因型工人血铅水平增高，对铅毒性易感。

Objective To investigate the relationship between genetic polymorphism of X-ray repair cross-complementing gene 3 （XRCC3） and susceptibility to lead poisoning in male lead-exposed workers. Methods Peripheral venous blood and morning urine samples were collected from 326 male lead-exposed workers in a storage battery factory in Fuzhou. Blood lead, urine lead, blood zinc protoporphyrin （ZPP）, blood calcium, and blood iron were measured. The genotype of XRCC3 was determined by polymerase chain reaction- restriction fragment length polymorphism method. The relationship between XRCC3 gene polymorphism and susceptibility to lead poisoning in male lead-exposed workers was analyzed. Results Genetic polymorphism of XRCC3 was seen in the 326 subjects. The frequency distribution of XRCC3 genotypes, XRCC3-241CC （wild type）, XRCC3-241CT （heterozygous mutation）, and XRCC3-241TY （homozygous mutation）, was in accordance with the Hardy-Weinberg equilibrium （P〉0.05）. There were no significant differences in urine lead, blood ZPP, blood calcium, and blood iron between the lead-exposed workers with different XRCC3 genotypes （P〉O.05）. The workers with XRCC3-241CT/Tl＂ had a significantly higher mean blood lead level than those with XRCC3- 241CC （P〈0.05）. With a blood lead level of 1.90 μmol/L as the cutoff value, the chi-square test and logistic regression analysis showed that the proportion of workers with XRCC3-241CT/TT was significantly higher than that of workers with XRCC3-241CC in the subjects with high blood leads （P〈0.05） and that the risk of high blood lead was significantly higher in the workers with XRCC3-241CT/TT than in those with XRCC3-241CC （OR =2.34, 95% CI=1.61-5.13）; the multivariate linear regression analysis showed that the workers with XRCC3-241CT/TF had high blood lead levels （β=0.116, P〈0.05）, the workers with smoking habit demonstrated marked lead absorption （β=0.188, P〈0.05）, good individual protection could reduce lead absorption （β=-0.247, P〈0.05）, and the individuals with low serum Ca2＋ levels had high blood lead levels （β=-0.145, P〈0.05）. Conclusion When exposed to the same level of lead at workplace, the workers with XRCC3-241CT/Tr have a significantly higher blood lead level than those with XRCC3-241CC, so the genotype of XRCC3-241CT/TT accounts for higher susceptibility to lead poisoning.