香烟烟雾暴露对未成年小鼠齿状回神经发生和小胶质细胞的影响

为探讨香烟烟雾暴露(cigarette smoking exposure,CSE)对未成年小鼠的神经发生及学习记忆的影响,本研究用亲和组织化学方法,以5-溴脱氧尿苷(5-bromodeoxyuridine,BrdU)和西非单叶豆同工凝集素-B4(Bandeirae SimplicifoliaIsolectin-B4,BSI-B4)分别标记新生细胞和小胶质细胞(microglia,MG),观察了CSE小鼠齿状回内的神经发生及MG数目的变化,并通过Morris水迷宫训练测验其空间学习能力。结果显示:CSE下小鼠齿状回内的神经发生降低,MG数目显著减少;而在水迷宫的学习中,CSE组的逃避潜伏期亦明显长于对照组(P<0.05)。上述结果表明CSE损害了未成年小鼠齿状回内的神经发生,抑制了MG的激活,同时小鼠的空间学习能力与神经发生及激活的MG数量平行变化。此结果提示CSE造成的学习能力降低可能与齿状回神经发生及MG减少有关。

The effects of cigarette smoking exposure on the neurogenesis and microglia in dentate gyrus of adolescent mice

To investigate the effect of cigarette smoking exposure(CSE)on the adolescent mice,we used the methods of immunohistochemistry to label the newly formed cells and microglia(MG)with 5-bromodeoxyuridine(BrdU)and Bandeirae Simplicifolia Isolectin-B4(BSI-B4),respectively,which reflex the changes of neurogenesis and the amount of MG in dentate gyrus(DG)of the mice after exposure to the cigarette smoking,and through the Morris water maze(MWM)training,we tested their spatial learning ability.The results showed that the neurogenesis was decreased and the quantity of MG degraded markedly,and the CSE groups hold evident longer escape latency than control group(P<0.05)in the process of MWM learning.These results suggest that CSE impairs the neurogenensis of adolescent mice and inhibit the activation of MG in the DG,meanwhile the spatial learning ability parallels with the neurogenesis and the population of activated MG.CSE engendered reduction of learning ability is possibly due to the diminution of neurogenesis and MG.