Study of Biological-Effect Monitoring to Arsenic Exposure

近年来，饮用水砷污染是造成我国大规模慢性砷中毒的原因之一。iAs的暴露剂量约为每天1 mg或更多。36名受试者的平均尿总砷（iAs +代谢物）水平为2.39 = 0.67 μ As/L，由15% iAs、20%单甲基砷（MA）和65%二甲基砷（DMA）组成。慢性砷中毒患者尿MA和DMA的排泄趋势与尿砷的排泄趋势一致，并有增加的趋势。通过体内iAs的第二甲基化观察到了性别差异。29名受试者头发中总砷含量平均为1.82 μ g/g，由88%iAs和12%DMA组成，头发中DMA含量随iAs暴露量的增加而增加，皮肤组织学观察未见明显改变。相比之下，与对照动物相比，暴露动物的真皮显示出中等厚度的胶原束。12只暴露动物中有7只在真皮中显示出明显增厚的胶原束。与对照组动物相比，暴露组动物的GM-CSF和TGF α mRNA表达中度增强。这一结果表明砷诱导小鼠皮肤紧绷，并表明胶原蛋白产生的上调可能是砷中毒中皮肤紧绷的原因，可能是通过诱导GM-CSF和TGF α。

In recent years, arsenic contamination to drinking water is a cause, and a large-scale chronic arsenic poisoning occurs in China. Exposure doses of iAs were approximately 1 mg or more a day. The mean urinary total arsenic (iAs + metabolites) level in the 36 subjects was 2.39 = 0.67 mu As/L, composed of 15% iAs, 20% monomethylated arsenic (MA) and 65% dimethylated arsenic (DMA). The tendency for excretion of urinary MA and DMA keep pace with lAs, and increased was observed by the patients with chronic arsenic poisoning. The difference of sex difference was observed by 2nd methylation for iAs in vivo. The mean hair total arsenic level in the 29 subjects was 1.82 mug As/g, composed of 88% iAs and 12% DMA.As for DMA concentration in hair, the tendency which rose was shown to lAs exposure.Histopathologically, significant alteration in epidermis was not observed in mice of the exposed groups. In contrast, dermis in the exposed animals showed moderately thick collagen bundles compared with control animals. Seven of 12 exposed animals showed significantly thickened collagen bundles in dermis. The mRNA expressions of GM-CSF and TGFalpha were enhanced moderately in the exposed animals compared with those of control animals. This result shows arsenic induces tight skin in mice and suggests that up-regulations of collagen production might responsible on the tightened skin in arsenic poisoning probably via induction of GM-CSF and TGFalpha.