饮水砷暴露与人外周血白细胞组蛋白H3K4me3、H3K79me3关系的探讨

A study on the relationship between arsenic exposure and H3K4me3 and H3K79me3 in human peripheral leukocyte histone

目的 观察饮水砷暴露对人群外周血白细胞中组蛋白H3第4位赖氨酸三甲基化（H3K4me3）和H3第79位赖氨酸三甲基化（H3K79me3）修饰水平的影响，分析砷暴露与H3K4me3和H3K79me3修饰水平的关系。方法 采用整群抽样的调查方法，在山西省和吉林省饮水型地方性砷中毒典型病区开展现场调查，选择饮水年限≥10年的当地常住居民281人作为调查对象。受检人群按照饮用水砷含量分为对照组（水砷含量≤0.01 mg／L，60例）、低水砷暴露组（ 〉 0.01- 0.05 mg／L，61例）、中水砷暴露组（ 〉 0.05 - 0.10 mg／L，50例）、高水砷暴露组（ 〉 0.10 mg／L，110例）。采集调查对象的饮用水样、即时尿样和外周血样。采用原子荧光法检测饮水砷含量和尿砷含量；斑点杂交方法（Dot Blotting）检测外周血白细胞中组蛋白H3K4me3和H3K79me3的修饰水平。结果 对照组，低、中、高水砷暴露组间年龄（61.50、60.00、59.50、59.50岁）、性别（男：20、27、17、40例，女：40、34、33、70例）、体质指数（BMI）、吸烟及饮酒情况比较，差异无统计学意义（P均 〉 0.05）。对照组，低、中、高水砷暴露组水砷含量中位数分别为0.005、0.024、0.076、0.150 mg／L；尿砷含量中位数分别为0.011、0.018、0.061、0.134 mg／L；水砷累积暴露量中位数分别为0.342、1.641、5.273、7.716 mg，组间比较差异有统计学意义（H = 256.041、88.615、218.610，P均 〈 0.01）。对照组，低、中、高水砷暴露组人群外周血白细胞中H3K4me3（0.100、0.059、0.083、0.083）、H3K79me3（0.049、0.036、0.055、0.052）修饰水平比较，差异无统计学意义（H = 1.488、2.097，P均 〉 0.05）。外周血白细胞H3K4me3、H3K79me3修饰水平与水砷含量、尿砷含量、水砷累积暴露量呈正相关关系（r = 0.245、0.221，0.299、0.318，0.149、0.149，P 〈 0.01或 〈 0.05）；H3K4me3与H3K79me3修饰水平之间呈正相关关系（r = 0.811，P 〈 0.01）。结论 饮水砷暴露虽然与人群外周血白细胞中H3K4me3和H3K79me3修饰水平存在正相关关系，但仍需扩大样本量进一步研究。

Objective To observe the effect of arsenic exposure to drinking water on thelevel of histone 3 lysine 4 trimethylation （H3K4me3） and histone 3 lysine 79 trimethylation （H3K79me3） in peripheral blood leukocytes of human, and to analyze the relationship between arsenic exposure and H3K4me3, H3K79me3 modification levels. Methods A cluster sampling survey was carried out in typical endemic arsenicosis areas of Shanxi and Jilin provinces. Two hundred eighty-one local residents with a drinking water age of ≥10 years were selected as the survey subjects. According to the arsenic content of drinking water, the tested population was divided into control group （water arsenic content ≤0.01 mg/L, 60 cases）, low water arsenic exposure group （ 〉 0.01 - 0.05 mg/L, 61 cases）, medium water arsenic exposure group （ 〉 0.05 - 0.10 mg/L, 50 cases）, and 110 cases of high water arsenic exposure group （ 〉 0.10 mg/L）. Drinking water samples, immediate urine samples and peripheral blood samples were collected from the subjects. Arsenic content in drinking water and urinary arsenic content were determined via the atomic fluorescence method; histone H3K4me3 and H3K79me3 in peripheral blood leukocytes were determined by dot blot hybridization （Dot Blotting）. Results There were no statistically significant differences in age （61.50, 60.00, 59.50, 59.50 years old）, different gender （male： 20, 27, 17, 40 cases, female： 40, 34, 33, 70 cases）, body mass index （BMI）, smoking and drinking status between the control group, low, medium and high water arsenic exposure groups. Water arsenic content in the control group, low, medium and high water arsenic exposure groups （median： 0.005, 0.024, 0.076, 0.150 mg/L）, urinary arsenic content （0.011, 0.018, 0.061, 0.134 mg/L）, and water arsenic cumulative exposure levels （0.342, 1.641, 5.273, 7.716 mg） were compared between groups, the differences were statistically significant （H = 256.041, 88.615, 218.610, P 〈 0.01）. In the control group, low, medium and high water arsenic exposure groups, the modification levels of H3K4me3 （0.100, 0.059, 0.083, 0.083） and H3K79me3（0.049, 0.036, 0.055, 0.052） in peripheral blood leukocytes were not significantly different （H = 1.488, 2.097, P 〉 0.05）. The levels of H3K4me3 and H3K79me3 in peripheral blood leukocytes were positively correlated with water arsenic content, urinary arsenic content, water arsenic cumulative exposure levels（r = 0.245, 0.221; 0.299, 0.318; 0.149, 0.149; P 〈 0.01 or 〈 0.05）; there was a positive correlation between H3K4me3 and H3K79me3 modification levels （r = 0.811, P 〈 0.01）. Conclusion There is a positive correlation between arsenic exposure through drinking water and the levels of H3K4me3 and H3K79me3 in the peripheral blood leukocytes of the population, but it is necessary to expand the sample size for further study.