ABSTRACT
Objective To detect the global level of histone 4 lysine 20 (H4K20) methylation and its relation with DNA damage-repair in peripheral blood cell of arsenic-exposed residents in the coal-contaminated arsenism areas in Guizhou,in order to provide a basis to deepen the interpretation of the role of arsenic in inhibiting DNA damage-repair.Methods Jiaole village in coal-burning-borne arsenism areas in Xingren County of Guizhou was selected as the survey point,and 115 cases of arsenic-exposed residents were selected as the arsenic exposed group on the basis of physical examination.Moreover,53 residents from one village of non-epidemic area neighboring the diseased area were selected as controls.Hair and peripheral blood samples of these subjects were collected,and the histone protein was extracted from the lymphocytes separated from blood samples.The hair samples were digested with microwave digestion instrument,and the hair arsenic content was tested via the inductively coupled plasma-mass spectrometry (ICP-MS) method;the level of H4K20 1,2,3 methylation (H4K20me2,me2,me3) in peripheral blood cell was tested by enzyme-linked immunosorbent assay (ELISA);DNA damage of peripheral blood cell was measured by single cell gel electrophoresis (SCGE).Results The testing results of hair arsenic contents showed that the arsenic levels of hair in arsenic exposed group [0.30 (0.19-0.46)μg/g] were significantly higher than those of control group [0.12 (0.08-0.18) μg/g,F=11.968,P ＜ 0.05].Compared with the control (0.44 ± 0.14,0.99 ± 0.41,1.06 ± 0.33),the level of H4K20me1 (0.60 ± 0.29) in arsenic exposed group was higher (F =2.513,P ＜ 0.05),H4K20me2 (0.75 ± 0.26) was lower (F =4.707,P ＜ 0.05),and H4K20me3 (1.20 ± 0.62) was of no significant difference (F =0.582,P ＞ 0.05).The detecting results of DNA damage of the lymphocytes separated from peripheral blood showed a statistically significant increase (F =9.307,9.457,all P ＜ 0.05) in TailDNA％ and Olivetailmoment in arsenic exposed group [Median (M):10.75,11.69]compared with those of control group (M:2.12,1.16).The correlation analysis indicated that the arsenic levels of hair of subjects were positively correlated with H4K20me1 (r =0.214,P ＜ 0.05) and inversely with H4K20me2 (r =-0.224,P ＜ 0.05);H4K20me1 was positively associated with TailDNA％ (r =0.383,P ＜ 0.05) and Olivetailmoment (r =0.380,P ＜ 0.05);H4K20me2 was inversely associated with TailDNA％ (r =-0.290,P ＜ 0.05) and Olivetailmoment (r =-0.298,P ＜ 0.05).Conclusion H4K20 methylated modification makes a response to arsenic exposure of human body,the alteration of H4K20mel/me2 may participate in regulating DNA damage-repair induced by arsenic in vivo.
ABSTRACT
The content of zinc and copper in the hair of 321 persons was detected by an atomic absorption spectropolarimeter. The subjects included young healthy group (35 men, 30 women), middle aged healthy group (72 men, 18 women), arteriosclerosis group (81 men, 20 women), cerebral embolism group (23 men, 8 women) and its control group (23 men, 8 women). The ratio of zinc to copper in the hair of the persons suffered from cerebral embolism was obviously higher than that of healthy controls. By comparing the function of the susceptible factors in cerebral embolism with Feisher's determination analysis method, diastolic pressure was found to be 75.02 percent, the ratio of zinc to copper 16.32 percent. The diagnostic coincidence was found to be above 82 percent.