Study of Biological-Effect Monitoring to Arsenic Exposure

近年来，饮用水砷污染是一个原因，中国发生了大规模的慢性砷中毒。碘化钾的暴露剂量约为每天1毫克或更多。36例受试者尿总砷（iAs +代谢物）平均水平为2.39 = 0.67 μ As/L，其中iAs占15%，单甲基化砷（MA）占20%，二甲基化砷（DMA）占65%。慢性砷中毒患者尿MA和DMA的排泄趋势与lAs保持同步，且呈上升趋势。通过体内iAs的第2甲基化观察性别差异。29名受试者的平均头发总砷含量为1.82微克/克，其中砷含量为88%，DMA含量为12%。头发中DMA浓度随lAs暴露呈上升趋势。在组织病理学上，暴露组小鼠表皮未见明显改变。相反，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只真皮胶原束明显增厚。与对照动物相比，暴露动物GM-CSF和TGFalpha mRNA表达适度增强。结果表明，砷可诱导小鼠皮肤紧致，并提示砷中毒后皮肤紧致可能是通过诱导GM-CSF和TGFalpha引起的。

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.