切割穹窿海马伞后海马齿状回内Lhx8的表达变化及其对RGCs向胆碱能神经元分化的影响

Dynamic expression of Lhx8 in hippocampal dentate gyrus after fimbria-fornix transection and its effects on differentiation of RGCs into cholinergic neurons

目的:明确Lhx8在SD大鼠切割穹窿海马伞后海马齿状回颗粒下层和门区中的表达变化。方法:切割SD大鼠穹窿海马伞,成功制备海马去神经支配动物模型后,通过Western Blot的方法检测切割后第1、3、7、14、21、28 d海马中Lhx8蛋白的表达变化;通过免疫组织化学方法检测切割后第7天海马齿状回颗粒下层和门区中Lhx8阳性细胞的表达定位,并通过免疫荧光化学方法检测Lhx8/ChAT双标阳性细胞的共定位情况;切割SD大鼠穹窿海马伞并制备海马提取液,将其加入至细胞培养液中,模拟体内海马神经再生微环境,检测培养的海马放射状胶质细胞(radial slia cells,RGCs)向胆碱能神经元分化的情况。结果:切割穹窿海马伞后第7 d,Lhx8蛋白表达量较其他各时相点明显增高;海马齿状回颗粒下层和门区中Lhx8阳性细胞数目和光密度也明显高于正常侧,Lhx8/ChAT双标阳性细胞数目也较正常侧增多;体外细胞培养,切割穹窿海马伞侧海马提取液也较正常侧海马提取液更能促进海马放射状胶质细胞向胆碱能神经元的分化。结论:切割穹窿海马伞后,Lhx8表达明显上调,与海马齿状回的胆碱能神经再生有关。

Objective： To detect dynamic Lhx8 expression in hilus and subgranular zone of hippocampal dentate gyrus after fimbria-fornix transection. Methods： The right fimbria-fornix of rats was trnasected to produse hippocampal denervation animal model, the Lhx8 protein expression was investigated by Western Blot on days 1, 3, 7, 14, 21 and 28 after fimbria-fornix transection; the expression and location of Lhx8 positive cells on day 7 in hilus and subgranular zone of hippocampal dentate gyrns were detected by immunohistochemistry, and the co-location of Lhx8/ChAT positive cells were detected by immunofluorescence; after fimbria-fomix transection hippocampal extracts were prepared and added into culture medium to mimic the hippocampal neurogenesis nich in vivo, then the differentiation of cholinergic neurons from hippocampal radial glia cells （RGCs） was investigated in vitro. Results： The protein expression of Lhx8 was obviously higher on d 7 after fimbria-fomix transection than that in other groups; the number and optical density of Lhx8 positive cells in transected hippocampal subgranular zone and hilus were higher than that in normal side, and the number of Lh8/ChAT double labeled cells was also higher than on the normal side; transected hippocampal extracts increased more cholinergic neuronal differentiation than normal hippocampal extracts in vitro. Conclusion： The expression of Lhx8 was upregulated after fimbria-fomix transaction and was associated with hippocampal cholinergic neurogenesis.