接苯工人外周血染色体损伤研究

Damage of chromosome in peripheral lymphocytes of occupational benzene-exposed workers

为探讨苯的遗传损伤 ,用G分带技术 (5 0中期分裂相 人 )和常规染色体分析 (10 0中期分裂相 人 )研究了职业接触苯工人 (4 2 )和正常对照组工人 (4 2 )外周血淋巴细胞染色体数目和结构畸变。苯组畸变细胞数明显增加 (P <0 0 5 ) ,42和 43条染色体分别呈明显差异 (P <0 0 5 )和非常明显差异 (P <0 0 0 1) ;四倍体占接苯组超二倍体总数的 82 43% ,亚二倍体频数≤ 10 2 3mg m3 (2 0人 )和 >10 2 3mg m3 (2 2人 )组分别呈明显和非常明显升高 ,苯组男性四倍体呈非常明显升高 (P <0 0 1) ,而女性 42和 43条染色体依次显示明显 (P <0 0 5 )和非常明显差异 (P <0 0 1)。苯组和对照组结构畸变细胞数有显著差异 (P <0 0 5 )。接苯组男性结构畸变细胞数明显升高 (P <0 0 5 )。结构畸变类型主要是单体裂隙、单体断裂和缺失。与对照组相比苯组主要集中在 2号染色体长臂 (5例细胞畸变 )和 10号长臂 (3例缺失 ) ,表明该部位可能存在脆弱位点。结果提示 ,长期接苯工人染色体数目和结构有明显损伤 ,男性比女性敏感 ;数目畸变以亚二倍体和四倍体为主 ,并呈剂量 -效应关系 ,结构畸变以缺失。

In order to study genetic damage caused by benzene exposure, this study reports the numerical chromosome aberration and the structural chromosome aberration in peripheral lymphocytes of occupationally benzene-exposed workers(42),and matched control workers(42), using G-banding technique (50 metaphases/subject) and conventional chromosome numerical and structure analysis (100 metaphases/subject).The benzene-group was divided into two group (≤102.3mg/m 3,n=20) and (>102.3mg/m 3,n=22). The frequency of numerical chromosome aberration in the exposed-group (18.55%) was significantly increased (P<0.05) compared to that in the control group (16.07%). The frequencies of 42 and 43 chromosomes in hypodiploid in the benzene-exposed group showed significant increase (P<0.05) and more significant increase (P<0.001), respectively; The frequencies of hypodiploid in ≤102.3mg/m 3 and >102.3mg/m 3 benzene-exposed groups showed significant(P<0.05) and more significant (P<0.01)difference, respectively, and also showed the dose-response relationship. The frequency of tetrasomy among male exposed workers was more significantly increased (P<0.01). The frequency of 42 and 43 chromosomes among female exposed workers showed significant increase (P<0.05) and more significant increase (P<0.01) respectively. The frequency of structural chromosome aberration in the benzene-exposed group was significantly increased (P<0.05) compared to the control group. The frequency of structural chromosome aberration among the male exposed workers was significantly increased(P<0.05). The types of the structural chromosome aberration mainly were chromatid gap, chromatid break and deletion. In comparison to control, most stable structural chromosome aberrations in exposed group accumulated mainly on chromosome 2 and 10 (5 aberrations on the long-arm of chromosome 2 and 3 deletions on the long-arm of chromosome 10).which suggests that these locations in the long-arms may exist fragile sites. This study firstly used G-banding technique associated with conventional chromosome analysis to confirm the special types and locations of structural chromosome aberration, sex differences of numerical chromosome aberration and the dose-response relationship in workers occupationally long-term exposed to benzene. The results showed that deletions were the main type of structural chromosome aberration and they all took place in long-arms. Whether the whole chromosome loss and the tetrasomy play an important role in the pathogenesis of benzene-induced leukemia deserve further study and follow up.