慢性饮水型砷暴露对人体DNA氧化损伤的影响

Effect of chronic arsenic exposure in drinking water on oxidative DNA lesions in humans

目的评价慢性饮水型砷暴露及暴露时间对人体DNA氧化损伤的影响。方法采用横断面研究对108名慢性饮水型砷暴露居民和75名对照居民进行调查；采用队列研究对64名慢性饮水型砷暴露者分别于砷暴露7年和9年时进行调查。用ELISA法测定尿8-羟基脱氧鸟苷（8-OHdG）水平，氢化物发生原子吸收分光光度法检测尿砷。结果横断面研究中，砷暴露组尿砷中位数为484．17mg/kg Cr，对照组为13．80mg/kg Cr，两组比较差异有统计学意义（t=32．566，P〈0．01）；儿童、成人尿8-OHdG中位数分别为16．60、21．88mg／kg Cr．明显高于对照组儿童（10．50mg／kg Cr）和成人（9．11mg／kg Cr），组间两两比较．差异有统计学意义（t值分别为5．049、6．913，P〈0．01）；暴露组儿童8-OHdG水平明显低于成人（t=-1．997．P〈0．05）。队列研究中．砷暴露7年时尿砷中位数为461．31mg／kg Cr，暴露9年时为422．90mg／kg Cr，二者比较未见明显差异（t=-0．250．P〉0．05）；砷暴露9年时儿童与成人尿8-OHdG中位数分别为23.46、24．30mg／kg Cr，与暴露7年时（14．29、18．38mg／kg Cr）比较均明显升高（t值分别为-2．949、-3．055．P〈0．01）。结论慢性饮水型砷暴露可导致机体DNA氧化损伤。在一定时期内．机体DNA氧化损伤可能随砷暴露时间的延长而加重。

Objective To evaluate effects of chronic arsenic exposure and arsenic exposure time on oxidative DNA lesions in humans. Methods A cross-sectional study was conducted in 108 subjects exposed to high concentrations of arsenic in drinking water and 75 control subjects. A cohort study was conducted in 64 subjects exposed to high levels of arsenic in drinking water for 7 or 9 years. Urinary 8-oxo-7,8-dihydrodeoxyguanine（8-OHdG） levels were analyzed by the enzyme-linked immunosorbent assay kit （ELISA）. Urinary arsenic concentration was detected with hydride generation atomic absorption spectroscopy. Results In the cross-sectional study, the median of urinary arsenic concentration was 484.17 mg/kg Cr for the arsenic-exposed group, and 13.80 mg/kg Cr for the control group, and the difference between the two groups was statistically significant （t = 32.57, P 〈 0.01 ）. The median of urinary 8-OHdG levels was 16.60 and 21.88 mg/kg Cr for arsenic-exposed children and adults respectively, much higher than control children（10.50 mg/kg Cr） and adults （9.11 mg/kg Cr）, and the difference was statistically significant （t = 5.049, 6.913, all P 〈 0.01 ）. Urinary 8-OHdG levels were significantly lower for children than adults in the exposed group （t = - 1.997, P 〈 0.05）. In the cohort study, the median of urinary arsenic concentration was 461.3 mg/kg Cr for the 7-year-exposed subjects and 422.90 mg/kg Cr for the 9-year-exposed subjects, and no significant difference was observed （t = - 0.250, P 〉 0.05）. The median of urinary 8- OHdG levels for 9-year-exposed children and adults were 23.46 and 24.30 mg/kg Cr respectively, significantly increased compared with those of 7-year-exposed（14.29 and 18.38 mg/kg Cr）, and the difference had statical significances （t = - 2.949,- 3.055, all P 〈 0.01 ）. Conclusions Chronic arsenic exposure can lead to oxidative DNA lesions in humans. The arsenic-induced DNA lesions may aggravate with the exposure time in a certain period.