Comparison of Urinary Arsenic and 8-hydroxy-2'-deoxyguanosine between Subacute and Chronic Arsenic-Exposed Subjects

Objective To compare urinary arsenic species and oxidative DNA lesions between subacute and chronic arsenicexposed subjects.Methods Sixty-five male patients(aged 20-62 years,concentration of arsenic in drinking water was 48.5 mg/L, time of arsenic exposure was 4-7 d)hospitalized in the central hospital of Fuxin during the accident of subacute arsenic poisoning in Fuxin city in December 2004 were selected as the subacute arsenic-poisoning group.The chronic high-(72 males,aged 18-73 years,concentration of arsenic in drinking water was 0.24 mg/L,time of arsenic exposure was 6 a)and low-arsenic-exposed subjects (40 males,aged 18-60 years,concentration of arsenic in drinking water was 0.02 mg/L,time of arsenic exposure was 10 a,without clinical symptoms of arsenicosis)were selected from arsenic contaminated areas around Hohhot,Inner Mongolia.The urine samples of subacute arsenic-poisoning subjects were collected immediately when they got into the hospital and before any treatment.The urine samples of chronic arsenic-exposed subjects were collected on site.The concentrations of urinary arsenic species were determined with cold trap hydride generation atomic absorption spectrometry.The level of urinary 8-hydroxy-2'-deoxyguanosine (8-OHdG)was analyzed with the enzyme-linked immunosorbent assay kit.Results In the arsenic-exposed groups,the levels of urinary arsenic species and total arsenic showed increase trends as the dose of arsenic exposure increased:subacute arsenicexposed groupchronic high-arsenic-exposed groupchronic low-arsenic-exposed group,and the differences among the 3 groups were significant(P0.05).The differences in urinary iAs%,MMA%and DMA%among the 3 groups were also significant(P0.05). iAs%and MMA%were the highest in the subacute arsenic-poisoning group,and lowest in the chronic low-arsenic-exposed group, DMA%were the lowest in the subacute arsenic-poisoning group,and the highest in the chronic low-arsenic-exposed group.The levels of urinary 8-OHdG for subacute arsenic-poisoning,and chronic high- and low-arsenic-exposed groups were 33.46 ng/g Cr (28.73-38.96 ng/mg Cr),25.32 ng/mg Cr(21.10-30.16 ng/mg Cr)and 9.52 ng/mg Cr(7.42-12.21 ng/mg Cr),and the differences among the 3 groups were significant(P0.05).Positive correlation between urinary 8-OHdG levels and concentrations of total arsenic in urine were observed in the subacute arsenic-poisoning,and chronic high-and low-arsenic-exposed subjects,and the pearson correlation coefficient was 0.849(P0.01),0.555(P0.01)and 0.733(P0.01),respectively.No significant correlation between urinary 8-OHdG levels and proportions of urinary arsenic species among subacute arsenic-poisoning subjects was seen, urinary 8-OHdG levels showed significant positive correlation with MMA%in chronic high- and low-arsenic-exposed subjects,the correlation coefficient was 0.540(P0.01)and 0.687(P0.01),respectively.Conclusion Arsenic methylation capacity will decrease and oxidative DNA damage will increase as the level of arsenic exposure increase.