Steward O, Torre E R, Phillips L L, Trimmer P A
Department of Neuroscience, University of Virginia Health Sciences Center, Charlottesville 22908.
J Neurosci. 1990 Jul;10(7):2373-84. doi: 10.1523/JNEUROSCI.10-07-02373.1990.
The present study evaluates the time course of increased expression of the mRNA for glial fibrillary acidic protein (GFAP) within the dentate gyrus and hippocampus after unilateral lesions of the entorhinal cortex. Levels of GFAP mRNA were evaluated by dot blot hybridization of mRNA isolated from the hippocampus and quantitative in situ hybridization. For dot blot hybridization, RNA was isolated from pooled hippocampi obtained from animals killed at 12 hr, 1, 2, 4, 6, 8, 10, 14, and 30 d postlesion. A separate set of animals killed at 2, 4, 6, 8, 10, 12, 14, and 32 d were prepared for in situ hybridization. The dot blot analyses of mRNA isolated from the hippocampus revealed that on the side ipsilateral to the lesion, the levels of GFAP mRNA increased rapidly, reaching a peak at 2 d postlesion. The increases were not evident by 12 hr postlesion, but by 24 hr, levels of GFAP mRNA were 5-fold higher than control, and by 48 hr, the levels were over 6-fold higher than control. The levels of GFAP mRNA decreased after 2 d postlesion. At 4 and 6 d postlesion the levels were about 2-fold higher than control. At later postlesion intervals, mRNA levels were comparable to the control. At 2 d postlesion, the levels of GFAP mRNA were also increased about 2-fold over control levels on the contralateral side. After 2 d, the levels of GFAP mRNA on the contralateral side were comparable to the control. In situ hybridization revealed a complex pattern of changes in the levels of GFAP. At 2 d postlesion, the levels of GFAP mRNA increased dramatically throughout the hippocampus bilaterally. The increases were most pronounced in the denervated portions of the neuropil; however, the levels of GFAP mRNA were also substantially elevated in laminae that do not receive direct projections from the entorhinal cortex. GFAP mRNA levels were also increased in other areas that receive projections from the entorhinal cortex, including the septum, lateral-dorsal thalamus, and entorhinal cortex contralateral to the lesion. In addition, GFAP mRNA levels were increased in regions bordering the ventricles throughout the brain, and over the surface of the tectum. After 2 d postlesion, the increases in the levels of GFAP mRNA were for the most part restricted to areas containing terminal degeneration. The generalized increases throughout the hippocampus were no longer apparent. Areas bordering the ventricles continued to exhibit higher labeling than in control animals, but this effect was not as prominent as at 2 d postlesion.(ABSTRACT TRUNCATED AT 400 WORDS)
本研究评估了内嗅皮质单侧损伤后齿状回和海马内胶质纤维酸性蛋白（GFAP）mRNA表达增加的时间进程。通过对从海马分离的mRNA进行斑点印迹杂交和定量原位杂交来评估GFAP mRNA水平。对于斑点印迹杂交，从损伤后12小时、1、2、4、6、8、10、14和30天处死的动物的合并海马中分离RNA。另一组在损伤后2、4、6、8、10、12、14和32天处死的动物用于原位杂交。从海马分离的mRNA的斑点印迹分析显示，在损伤同侧，GFAP mRNA水平迅速升高，在损伤后2天达到峰值。损伤后12小时升高不明显，但到24小时，GFAP mRNA水平比对照高5倍，到48小时，水平比对照高6倍以上。损伤后2天GFAP mRNA水平下降。在损伤后4天和6天，水平比对照高约2倍。在损伤后较晚的时间间隔，mRNA水平与对照相当。在损伤后2天，对侧GFAP mRNA水平也比对照水平升高约2倍。2天后，对侧GFAP mRNA水平与对照相当。原位杂交显示GFAP水平变化的复杂模式。在损伤后2天，双侧海马中GFAP mRNA水平显著升高。在神经毡的去神经支配部分增加最为明显；然而，在未接受内嗅皮质直接投射的层中，GFAP mRNA水平也大幅升高。在接受内嗅皮质投射的其他区域，包括隔区、背外侧丘脑和损伤对侧的内嗅皮质，GFAP mRNA水平也升高。此外，整个大脑脑室周围区域以及顶盖表面的GFAP mRNA水平升高。损伤后2天，GFAP mRNA水平的升高大部分局限于含有终末变性的区域。整个海马的普遍升高不再明显。脑室周围区域继续显示出比对照动物更高的标记，但这种效应不如损伤后2天明显。（摘要截于400字）
