脑缺血大鼠小胶质细胞转化生长因子β_1的表达

目的观察脑缺血时细胞转化因子TGF-β1的表达及其对脑缺血的影响。方法选择成年健康雄性Wistar大鼠64只,体重为250～400g。随机分为8组(正常对照组,假手术组,脑缺血5min后24、48、72、120、168、336h处死组,每组8只。采用四血管短暂前脑动脉缺血模型(four-vesselmodeloftransientforebrainischemia,FV-TFI),观察大鼠脑缺血后1～14dTGF-β1在不同部位的动态表达情况。结果正常对照组及假手术组,脑中有极少量的TGF-β1表达,海马区所有锥体细胞均可见很微弱的TGF-β1表达,无显著性差异(P>0.05);TGF-β在FV-TFI后的表达集中在皮质及皮质下的白质内,主要是小胶质细胞和极少数巨噬细胞,脑皮质缺血区锥体细胞亦有表达;TGF-β1的表达呈现一动态变化过程,且不同部位的表达存在差异,缺血后24h最高,14d后接近正常水平。结论TGF-β1与脑缺血损伤的整个过程密切相关,并在其中起着一定的作用。

The expression of TGF-β1 in microglias in ischemic rat''s brain

Objective To clarify the role of TGF-β 1 in brain,and observe it’s expression in ischemic rat’s brain.Methods The64adult male healthy Wistar rats,weighting250-400g,were divided into8groups randomly (normal control,sham-operated,and groups by various postischemia moment being killed,from24h to336h,6/per group),then they were made model of FV-TFI (four-vessel model of transient forebrain ischemia),being observed TGF-β 1 ’s expression in ischemic rat’s brain on various postischemia moment from1to14days.immunohistochemical staining was performed in the whole brain tissue sections to determine where the TGF-β 1 was detected,and the protein levels it was expressed.Results In normal and sham-operated animals,a faint signal corresponding to TGF-β 1 immunoreactive protein was detected within all pyramidal hippocampal neurons,indicating that endogenous levels of this protein were low and were not induced by the surgical manipulations.The main regions where TGF-β 1 was detected were cortex and subcortical white matter,with many TGF-β 1 positive microglias,some pyknotic pyramidal neurons in cortex,a few macrophages was also noticed positive.The levels of TGF-β 1 in ischemic animals brains were in a developed mode,with a summit at1day returning to baseline after14days.Conclusion TGF-β 1 takes part in the whole brain ischemia and plaies an important role in ischemic injury,and it would provide a new therapeutic method to ischemic cerebrovascular disease.