母爱剥夺对成年大鼠情绪及多巴胺转运蛋白基因表达的影响

Effect of maternal deprivation on emotion and expression of dopamine transporter in adult rats

目的:研究母爱剥夺对雄性大鼠成年后情绪及脑纹状体多巴胺转运蛋白(dopamine trans-porter,DAT)基因表达的影响,探讨DNA甲基化是否参与调控DAT基因的表达。方法:新生幼鼠随机分为实验组和对照组,实验组出生后第1至14天,每天母子分离6h。12周龄时,采用高架十字迷宫、旷场实验评定2组大鼠的情绪水平,采用RT-PCR法检测纹状体DAT mRNA表达水平,亚硫酸测序法检测DAT基因启动子区DNA甲基化水平。结果:实验组大鼠在新异环境中的探索能力下降、焦虑水平较低,大脑纹状体DAT mRNA表达显著低于对照组(P<0.05),DAT基因启动子区的DNA甲基化水平差异没有统计学意义(P>0.05)。结论:母爱剥夺对雄性大鼠成年后的情绪有持久的影响,且抑制纹状体DAT mRNA的表达;DNA甲基化可能不是DAT表达下降的机制。

Objective To investigate the change of emotion and striatum （DAT） expression in adult male rats experiencing maternal deprivation, and to dopamine transporter explore whether DNA methylation is involved in the regulatory mechanism of DAT expression. Methods Newborn rats were randomly divided into 2 groups ： a maternal separation group （ n = 16 ） and a control group （ n = 14 ）. The maternal deprivation group were separated from their mother for 6 hours （09：00-15：00） per day from postnatal day 1 to 14, while the controls （ n = 14 ） without the deprivation. When the rats in the 2 groups were 12 week, their spontaneous anxiety levels and exploratory ability in novel environments were assessed by an elevated plus maze and an open field test. DAT mRNA expression in the striatum was detected by reverse transcription-PCR, and its DNA methylation level was measured by bisulfated DNA sequencing. Results Maternally-deprived rats showed lower ability of exploring in a new environment and lower levels of anxiety than the controls. The expression of DAT mRNA in the striatum of the maternal separation group （ 0. 236 ±0. 043 ） was significantly lower than that in the control group （0.480±0. 107） （P 〈0.05）. However the DNA methylation level in the promoter region of DAT was not significantly different between the 2 groups. Conclusion Maternal deprivation influenced the emotion and expression of dopamine transporter in adult rats and DNA methylation may not be involved.