氯化甲基汞对大鼠发育不同阶段脑染色质结构的影响

EFFECT OF METHYLMERCURY CHLORIDE ON THE BRAIN CHROMATIN STRUCTURE IN RATS IN VARIOUS STAGES OF DEVELOPMENT

本文用Hewish和Burgoyne法分离纯化大鼠脑细胞核,采用脑细胞核缺口翻译分析法,探讨孕鼠于妊娠器官发生期,经腹腔连续给予5天氯化甲基汞(2mg/kg体重)后,对大鼠发育不同阶段脑染色质结构的影响。实验结果表明,接触氯化甲基汞组大鼠脑细胞核,分别经DNase 1和EcoR 1核酸内切酶消解后,进行核缺口翻译测定,生后3天大鼠脑细胞核,分别经两种酶处理后,其~3H—dAMP掺入量均明显低于相应未接触氯化甲基汞对照组。氯化甲基汞对大鼠发育过程中脑染色质结构的影响,可能与胎、幼鼠对甲基汞神经毒性的易感有密切关系。

Brain nuclei of rats were separated and purified with Hewish-Burgoyne method. Pregnant rats were injected i. p. with methylmercury chloride (CH3HgCl) of a dosage of 2mg/kg sequently for 5 days in the organogenetic period. We investigated the effect of CH3HgCl on brain chromatin structure of natal rats of various stages of development .Brain nuclei of rats exposed to CH3HgCl were treated with endonucleases DNase I or EcoR I and detected by means of nick translation of nuclei. It was found that incorporation of 3H--dAMP appeared significantly lower than that of the unexposed rats of 3 days after birth (P<0.05) .We suggested that the effects of CH3HgCl on chromatin structure of the brain nuclei in different stages of development may be closely related to hypersensi-tivity of the fetal and infant rats to neurotoxicity of CH3HgCl.