δ-氨基乙酰丙酸脱水酶基因多态性对职业铅接触工人血铅和锌原卟啉的影响

The Effect of δ-Aminolevulinic Acid Dehydratase Gene Polymorphism on Blood Lead and Zinc Protoporphyrin Levels among Occupationally Lead-Exposed Workers

[目的 ]研究δ 氨基乙酰丙酸脱水酶 (ALAD)基因多态性对职业铅接触工人血铅 (PbB)和锌原卟啉 (ZPP)的影响。 [方法 ]采集 170名上海市某蓄电池厂职业铅接触工人外周静脉血样 ,多聚酶链式反应 (PCR)和限制性内切酶 (MspⅠ )限制性片段长度多态性 (RFLP)方法进行ALAD基因分型分析 ,用PE 80 0型原子吸收分光光度计和ZPP 3 80 0型血液锌原卟啉测定仪分别测定PbB和ZPP含量 ,并分析其与基因型的关系。 [结果 ]①ALAD11纯合子基因型者有 15 4名 ,占90 5 9% ;ALAD12杂合子基因型者有 16名 ,占 9.41% ;未检出ALAD2 2纯合子基因型者 ;②ALAD1和ALAD2等位基因分布频率分别是 95 .2 9%和 4.71% ;③在同等外暴露条件下 ,ALAD12杂合子基因型组工人血铅水平 ( 1.0 4± 0 .48μmol/L)明显高于ALAD11纯合子基因型组工人血铅水平 ( 0 .78± 0 .3 4μmol/L) ,且差异有统计学意义 ;④ALAD12基因型工人锌原卟啉(ZPP)含量比ALAD11基因型者稍低 ,但差异没有统计学意义 ,前者为 ( 0 .42± 0 .2 4) μmol/L ,后者为 ( 0 .46± 0 .41) μmol/L。[结论 ]ALAD2等位基因频率与文献报道的亚洲人群的结果相近 ,符合Hardy Weinberg平衡 ,在同样职业铅暴露环境下 ,具有ALAD2等位基因的工人血铅水平增高 。

Objective] To investigate the association between δ-aminolevulinic acid dehydratase(ALAD) gene polymorphism and blood lead (PbB) and zinc protoporphyrin (ZPP) levels in the occupationally lead-exposed workers and identify the contribution of the ALAD genotype to the body lead burden. [Methods] 170 blood samples of occupationally lead-exposed workers were selected from a storage factory in Shanghai Pudong District. An assay based on the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) technique of restriction enzyme MspⅠwas used to determine the genotype of the ALAD gene. The levels of PbB and ZPP were also detected in the same time, using PE-800 graphite furnace atomic absorption spectroscopy and ZPP-3800 hematofluorometer. [Results] ① The gene distribution of the ALAD isozyme phenotypes in these occupationally exposed workers was 154 ALAD11 homozygotes (90.59%),16 ALAD12 heterozygotes (9.41%), but there are no ALAD22 homozygotes. ② The frequencies of ALAD1 and ALAD2 alleles are 95.29% and 4.71%. ③ The PbB level of the workers with ALAD12 heterozygotes(1.04±0.48 μmol/L) is significantly higher than that with ALAD11 homozygotes(0.78±0.34 μmol/L), (P<0.05). ④ The ZPP level of the workers in ALAD12 heterozygous subgroup is a little lower than that in ALAD11 homozygous subgroup, but there is no statistical difference. And the ZPP levels are (0.42±0.24) μmol/L and (0.46±0.41) μmol/L,respectively. [Conclusion] The frequencies of ALAD1 and ALAD2 alleles in this population of occupationally lead-exposed workers are similar with several previous reports studied in the Asian people, which accord with Hardy-Weinberg Equilibrium in Genetics. We can conclude, with the same occupationally exposed level at workplace,the workerswith ALAD2 allele have higher PbB levels than that of ALAD11 homozygous individuals. The ALAD2 genotype can increase lead body burden and hematologic toxicity to workers,that might be due to the increased lead load in body.