ABSTRACT
Objective To understand the changes of skin lesions in population exposed to arsenic through drinking-water in Inner Mongolia after changing water source for 12 years,and to evaluate the long-term harmful effects and the delayed injury to human body due to arsenic exposure and the effect of changing water.Methods The stratified random cluster sampling investigation objects (data derived from the Inner Mongolia Autonomous Region Comprehensive Center for Disease Control and Prevention) of the arsenic exposure area before water reform (2004) as the foundation,in 2017,we selected three administrative villages (changed water in 2005) in Bayan Nur City of Inner Mongolia as survey sites.The objects of this study were residents who had been living in the survey site and were eligible for previous survey (n =80,35 males and 45 females).To compare the skin damage of the residents exposed to arsenic before and after the water changed,the water samples of the survey objects were measured arsenic content.According to the content of water arsenic,the respondents were divided into low,medium and high exposure groups (10-,150-,≥300 μg/L),to analyze clinical classification in skin damage before and after changing water.Results The water arsenic content after changing [1.42 (0.18-33.45) μg/L] was lower than those before the changes [238.20 (14.56-824.70) μg/L,Z =-8.34,P ＜ 0.05].A total of 63 persons with skin keratinization,7 persons with hyperpigmentation and 19 persons with depigmentation were identified after the changes of drinking water source,while 38,3 and 18 persons were respectively found before the changes.The detection rate of skin keratinization after water changes was significantly higher than that before water changes [78.8％ (63/80) vs 47.5％ (38/80),x2 =16.78,P ＜0.05].According to the clinical classification of skin damage,23 patients were normal,44 patients were suspicious,10 patients were mild,and 3 patients were moderate or severe after the water changes,compared with those before the water changes (38,18,6 and 18 persons were respectively found),the clinical fractional suspicious detection rate of skin damage in the arsenic exposed population increased,and the medium-severe detection rate decreased,and the differences were statistically significant (x2 =17.80,12.33,P ＜ 0.05).The detection rate of the clinical score of moderate-severe skin damage in men was significantly decreased,and the difference was statistically significant (x2 =7.65,P ＜ 0.05).The normal detection rate of female skin lesions was reduced,and the rate of suspected detection was increased (x2 =5.48,7.65,P ＜ 0.05).In the high-and medium-dose groups,41.9％ (13/31) and 42.9％(12/28) of the arsenic exposure population had a reduced clinical classification of skin damage.The ratios of clinical classification severity of skin damage in the high-,medium-and low-dose groups were 25.8％ (8/31),25.0％ (7/28),and 42.9％ (9/21).The differences were statistical significantly by linear trend chi-square test (x2 =12.96,P ＜ 0.05).Conclusions The skin lesions exposed to arsenic could be effectively improved after changing water.But the skin lesions still appear in some cases due to long-term chronic arsenic exposure.The long-term effects caused by arsenic should be explored persistently.
ABSTRACT
Objective To detect retinoid X receptor α (RXRα) mRNA expression in blood of subjects exposed to different concentrations of arsenic via drinking water, to analyze the relationship between RXRα mRNA expression and skin lesion caused by arsenic,and further to explore the skin lesion mechanism of arsenic. Methods Study sites were selected by molecular epidemiology method from high arsenic drinking water area of Bayannur City. Two hundred and thirty-five subjects who had been lived in high arsenic area for more than 10 years were selected;blood samples and water samples were collected from the subjects; according to arsenic concentration in drinking water,they were divided into four groups,<10 μg/L(control group),10-<100 μg/L(low dose group),100- <200 μg/L (middle dose group), and ≥200 μg/L (high dose group). Skin hyperkeratosis and pigment abnormity examination were conducted. The RXRα mRNA expression level in blood samples was detected by real-time quantitative PCR, and then the relationship between expression of RXRα mRNA and different levels of arsenic exposure,and skin lesion induced by arsenic were analyzed. Results ①The results showed that there was a dose-effect relationship between the prevalence of hyperkeratosis, pigment abnormity and arsenic exposure (χ2= 14.597, 12.825, P < 0.05); ②With increasing of arsenic exposure, RXRα mRNA expression in blood decreased firstly and then increased (F = 8.312, P < 0.05), which were significantly different statistically from those of control [(1.20 ±0.53)×10-3]and low dose groups[(0.92 ± 0.49)×10-3,P<0.05];RXRα expression was significantly higher in high dose group[(1.40 ± 0.45)×10-3]than those of middle and low dose groups [(1.12 ± 0.58,0.92 ± 0.49)×10-3,P<0.05]; ③The RXRα mRNA expression in people with different level of skin damage (hyper keratosis and pigment abnormity)were statistically significant(F=4.206,4.389, P< 0.05); degree Ⅲ[(1.98 ± 0.38) × 10-3] hyperkeratosis patients compared with degree Ⅰ [(1.11 ± 0.52) × 10-3] and degree Ⅱ [(1.13 ± 0.42) × 10-3], RXRα mRNA expression was significantly different (P < 0.05), degree Ⅱ and higher degrees [(1.61 ± 0.54) × 10 -3] pigment abnormity patients compared with control [(1.15 ± 0.52)×10-3],RXRα mRNA expression was significantly different (P < 0.05). Conclusions Chronic arsenic exposure has an effect on RXRα mRNA expression in blood. There is a relationship between abnormal expression of RXRα mRNA and skin lesion induced by arsenic.