B族维生素上调KDM5家族减轻PM2.5诱发孕鼠抑郁样行为的作用及机制

B vitamins attenuate depression-like behavior induced by PM2.5 exposure through up-regulating KDM5 in pregnant mice

目的:探讨孕期B族维生素(VitB)干预是否改善了PM2.5暴露所致的孕鼠抑郁样行为及可能的表观遗传学机制。方法:采用气管雾化的方式建立孕期PM2.5损伤模型,同步进行B族维生素干预。将孕鼠随机分为PBS对照组、PM2.5暴露组和VitB干预组。采用旷场实验分析孕鼠抑郁样行为的变化;分离孕鼠大脑皮层,采用NeuN免疫荧光染色及高尔基染色检测神经元的损伤情况,Western blot检测突触蛋白的表达变化;采用RT-qPCR、Western blot和免疫荧光双标染色检测孕鼠大脑皮层KDM5家族的表达变化和分布情况,及组蛋白H3K4的甲基化水平。结果:B族维生素干预能明显改善PM2.5暴露所致孕鼠的抑郁程度,中央区活动时间显著延长(P<0.05),中央区活动距离和旷场运动总距离增多(P<0.05);B族维生素干预能缓解PM2.5导致的孕鼠大脑皮层神经元损伤,树突形态的复杂性得到保护,突触相关蛋白——突触小泡蛋白、生长相关蛋白43和突触后致密蛋白95水平显著回升(P<0.05);大脑皮层KDM5A、KDM5B和KDM5C的mRNA和蛋白水平均显著升高(P<0.05),组蛋白H3K4me3的蛋白水平明显得到纠正;大脑皮层KDM5A^(+)/NeuN^(+)、KDM5B^(+)/NeuN^(+)和KDM5C^(+)/NeuN^(+)双阳性神经元明显增多,大脑皮层椎体神经元恢复至正常。结论:孕期给予B族维生素干预,可以通过上调KDM5纠正大脑皮层组蛋白的甲基化水平,从而减轻PM2.5造成的神经元损伤及孕鼠抑郁样行为。

AIM:To investigate the effects of B vitamins(VitB)intervention on depression-like behavior induced by PM2.5 exposure in pregnant mice,and to explore the potential epigenetic mechanisms.METHODS:Exposure of female mice to PM2.5 during pregnancy was established by endotracheal aerosolization,with VitB intervention performed synchronously.The pregnant mice were randomly divided into 3 groups:control(PBS)group,model(PM2.5+PBS)group,and intervention(PM2.5+VitB)group.The behavioral changes of mice were analyzed by open field test.Immunofluorescence staining for NeuN and Golgi staining were employed to detect neuronal impairment.Western blot was conducted to analyze the levels of synaptic proteins.The level and distribution changes of KDM5 family,and the methylation levels of histone H3K4 in mouse cerebral cortex were investigated by RT-qPCR,Western blot and double-labeled immunofluorescence staining.RESULTS:Intervention with VitB significantly reduced depression-like behavior induced by PM2.5 exposure in pregnant mice,the duration within the central area in intervention group was significantly extended(P<0.05),and the distance within the central area and the total distance in open-field test were enhanced(P<0.05).VitB alleviated cortical neuronal impairment induced by PM2.5 exposure in pregnant mice,the dendritic complexity in intervention group was protected,and the protein levels of synaptophysin,growth-associated protein-43 and postsynaptic density protein 95 were significantly elevated(P<0.05).The mRNA and protein levels of KDM5A,KDM5B and KDM5C in intervention group were significantly increased in cerebral cortex(P<0.05),and the methylation levels of histone H3K4me3 were significantly corrected.Double positive neurons of KDM5A^(+)/NeuN^(+),KDM5B^(+)/NeuN^(+),and KDM5C^(+)/NeuN^(+) in intervention group were significantly increased in the cerebral cortex,and pyramidal cells were recovered.CONCLUSION:The neuronal impairment and depression-like behavior induced by PM2.5 exposure in pregnant mice can be attenuated by VitB supplementation by up-regulating KDM5 to correct the methylation levels of H3K4.