亚砷酸钠致早期鸡胚胚胎发育毒性与基因甲基化的关系

摘要

Objective: To research the relationship between sodium arsenite (SA) - induced developmental toxicity in early chick embryos and global DNA methylation, and to investigate the effect of choline (CHO) supplementation on SA -induced embryo toxicity.Methods: The chick embryos were applied to investigate the effects of SA treatment and SA plus CHO co -treatment on embryo viability, body weight and morphology; the global DNA methylation by whole - mount immunofluorescence was measured; the relative gene expressions of bcl2, c - myc, cdkn2a and calb2 were detected by real - time polymerase chain reaction.Results: In the SA treatment group, the results showed that the reduction of embryo viability (P ＜ 0.01 ),loss of the body weight ( P ＜ 0.01 ), abnormal development, DNA hypomethylation ( P ＜ 0.01 ), reduction of gene expression of bcl2( P ＜0.05 ) and c - myc( P ＜0.01 ) regulated by methylation.Compared with groups treated with SA alone, there were no significant changes in embryos' survival rate and body weight in groups of SA - induced embryos co - treated with CHO.While the relative gene expression of c - myc ( P ＜ 0.01 ), cdkn2a ( P ＜ 0.01 ) and calb2 ( P ＜ 0.05 ) were significantly lower.Conclusion: SA can induce abnormal development in early chick embryos, which is probably due to the reduction of the global DNA methylation level But methyl donor choline can not antagonize the teratogenic effect induced by SA.%目的:研究亚砷酸钠致鸡胚胚胎毒性与基因组DNA整体甲基化的关系以及补充甲基供体胆碱对无机砷致胚胎毒性的影响.方法:以鸡胚为模式动物检测亚砷酸钠及其与胆碱联合处理对鸡胚生存能力、体重及形态的影响;采用whole-mount免疫荧光技术检测鸡胚基因组DNA整体甲基化水平;应用荧光定量PCR技术,研究受甲基化调节的bcl2、c-myc、cdkn2a,calb2基因在不同处理组鸡胚中的表达模式.结果:砷处理组鸡胚存活率下降(P<0.01),体重降低(P<0.01),并诱导鸡胚发育畸形,基因组DNA整体甲基化水平降低(P<0.01),受甲基化调节的基因bcl2(P<0.05)、c-myc(P<0.01)表达下调;补充甲基供体胆碱,未明显恢复鸡胚的生存力和改变鸡胚发育异常,对鸡胚基因组DNA整体甲基化水平亦无明显影响,但c-myc(P<0.01)、cdkn2a(P<0.01)、calb2(P<0.05)基因的表达均显著下降.结论:亚砷酸钠能够诱导鸡胚发育异常,其作用可能是通过降低基因组DNA整体甲基化水平实现.补充甲基供体胆碱不能拮抗其致畸效应.