卫生研究

目的研究有机氯农药人体内残留对生殖内分泌的影响。方法测定产妇静脉血中有机氯农药残留水平,分组研究其对产妇静脉血和脐带血中激素、胎盘和脐带组织中相关基因mRNA表达水平的影响。结果(1)产妇静脉血促卵泡激素(FSH)、雌二醇(E2)、孕酮(P)和脐带血FSH、黄体生成激素(LH)、E2随着体内有机氯农药残留水平的升高而增高,存在明显的剂量-效应关系;而静脉血LH和脐带血中孕酮随着体内残留水平的升高而下降,也存在明显的剂量-效应关系(P<0.01)。(2)胎盘组织α雌激素受体(αER)、β内啡肽(βEP)、促性腺激素释放激素(GnRH)和脐带组织αER、βEP基因的表达水平也随着有机氯农药体内残留水平的升高而增高,存在明显的剂量-效应关系(P<0.01)。(3)既往不良妊娠结局次数随着体内有机氯农药残留水平的升高而有增加趋势,各残留组与对照组比较差异均有显著性,但高残留组低于中残留组(P<0.01);婴儿平均出生体重各残留组均高于对照组,高残留组与对照组之间差异无显著性,而低、中残留组与对照组比较差异有显著性(P<0.05),且低残留组>中残留组>高残留组。结论有机氯农药体内代谢产物具有干扰内分泌功能,产生生殖和发育毒性作用,在总六六六的残留水平明显高于总DDT的混合暴露作用下,表现为拟雌激素作用为主。

Objective To explore effects of residues of organochlorine pesticides on reproductive endocrine in human. Methods The accumulative levels of the pesticides in the pregnant women's venous blood were determined and were grouped to understand the associations among the pesticides, hormones, and genes. Results (1) With the increase of blood burden of organochlorine pesticides, levels of the hormones such as follicle stimulating hormone (FSH), estradiol (E₂) and progesterone (P) in the maternal blood and FSH, luteinizing hormone (LH) and E₂ in the umbilical cord blood increased in dose-effect manner, respectively. However, the hormones, for example, LH in the women blood and P in the cords blood decreased respectively with the rising pesticides' levels and an obvious dose-effect relationship was found. (2)The expressional abundances of alpha-estrogen receptor (α-ER), beta-endorphin (β-EP) and gonadotropin releasing hormone (GnRH) in the placentae and α-ER and β-EP in the cord tissues went up respectively in dose-effect manner following the rising pesticides' burdens. (3)The times of the previous adverse pregnancy outcomes increased with the increase of the residues' burdens and there were significant differences between the control and various residue groups, but the times in the high-residue was smaller than that in the mid-residue group (P<0.01). The average weights of the newborn in various residue groups were heavier comparing to the control. There was no significant difference between the high residue group and the control. However, significances existed among the low, intermediate, and control group (P<0.05). Moreover, the rank from high to low was the low-residue, mid-residue and high residue group. Conclusion The residues of organochlorine pesticides (DDT and BHC and their metabolites) possess reproductive and developmental toxicities, and present mostly the estrogenic activity under the joint exposure in which the total BHC concentration was higher than that of the total DDT in maternal blood.