单侧液压脑损伤对大鼠双侧海马GFAP表达和CA1区突触传递的影响

目的研究单侧液压脑损伤(FPI)对大鼠双侧海马区胶质纤维酸性蛋白(GFAP)表达和CA1区突触传递的影响。方法建立大鼠单侧液压脑损伤模型,脑标本分为对照组(包括正常对照和假手术对照)、FPI损伤同侧组和FPI损伤对侧组。免疫组化法检测海马水平切片GFAP表达,对海马CA1区锥体神经元进行细胞内记录。结果FPI大鼠双侧海马齿状回门区和CA1区GFAP表达均比对照组明显增强。FPI损伤同侧组兴奋性输入-输出关系曲线的斜率比其他两组显著增大(P<0.05);FPI损伤同侧组和对侧组双脉冲易化(PPF)比值和抑制性突触后电位(IPSP)幅值均比对照组显著减小(P<0.05);FPI损伤同侧组和对侧组双脉冲抑制(PPD)比值均比对照组显著增大(P<0.05)。结论大鼠单侧液压脑损伤对双侧海马均可产生影响,导致双侧海马CA1区兴奋性突触传递增强,抑制性突触传递减弱。

Effects of lateral fluid percussion injury of brain on the bilateral GFAP expression in hippocampus and synaptic transmission in hippocampal CA1 area of rats

Objective To study the effects of lateral fluid percussion injury (FPI) of the brain on the expression of glial fibrillary acidic protein (GFAP) in the bilateral hippocampus and synaptic transmission in the bilateral CA1 areas of rats.Methods The lateral FPI rat model was made by applying an impact of 3.8~4.8 atm onto the left parietal cerebral cortex. The data were pooled in one of the three groups: the control group (including normal and sham injured), the FPI-ipsilateral group, or the FPI-contralateral group. Immunohistochemistry analysis was used to detect the GFAP expression in the dentate gyrus and CA1 area. Conventional intracellular recordings were made from the hippocampal CA1 pyramidal neurons.Results The GFAP expression in the dentate gyrus and CA1 area of hippocampus was significantly enhanced in both the FPI-ipsilateral and FPI-contralateral groups, compared with the control group. The excitatory postsynaptic potential (EPSP) input-output relationship curve (I-O curve) slope was significantly increased in the FPI-ipsilateral group, compared with the other two groups (P<0.05). The paired-pulse facilitation (PPF) ratios of EPSP and the inhibitory postsynaptic potential (IPSP) amplitudes were significantly decreased in the FPI-ipsilateral and FPI-contralateral groups, compared with the control group ( P<0.05 ). However, the paired-pulse depression (PPD) ratios of IPSP were significantly increased in the FPI- ipsilateral and FPI-contralateral groups, compared with the control group (P<0.05).Conclusion The results suggest that the lateral FPI can exert an influence on the bilateral hippocampus. The excitatory synaptic transmission is enhanced while the inhibitory synaptic transmission is depressed in the bilateral hippocampal CA1 area of rats with FPI.