环磷酰胺对脑缺血再灌注海马GFAP表达的影响

目的观察环磷酰胺对脑缺血再灌注后大鼠大脑海马区胶原纤维酸性蛋白（GFAP）表达的影响。方法设正常组、假手术组、缺血再灌注组（I／R）和环磷酰胺处理组（T），以改良Longa线栓法建立sD大鼠局灶性脑缺血模型。处理组缺血后1h给予环磷酰胺腹腔注射，处理组和I／R组均于缺血后2h形成再灌注，每组均分为三个时间段（24h、72h和5d）分别观察。应用免疫组织化学技术检测各组脑组织不同时段以及正常脑组织中海马GFAP的表达情况。结果脑缺血再灌注5d内，随着缺血时间的延长，GFAP在海马区星形胶质细胞中的阳性表达逐渐增多，缺血24h后即有表达，缺血再灌注72h后增多，5d后表达最高；经过环磷酰胺处理后，海马区GFAP表达减少（P〈0．05）。正常组及假手术组未见GFAP表达。结论大鼠脑缺血再灌注后5d内GFAP在海马中的表达与缺血时间呈明显的相关性，随着缺血时间延长而增加。用环磷酰胺处理后GFAP表达明显减少，提示环磷酰胺对缺血诱导的星形胶质细胞活化具有抑制作用，可能对脑缺血再灌注损伤的恢复起重要作用。

Effect of cyclophosphamide on the expression of GFAP of astrocytes in hippocampi of rats by after cerebral ischemia-reperfusion injury

Objective To observe the effect of cyclophosphamide on the expression of glial fibrillary acidic protein （GFAP） in hippocampi of rats after cerebral ischemia-reperfusion injury. Methods Rat middle cerebral ischemia- reperfusion （I/R） injury model was established with suture emboli method after the normal group, sham-operated group, ischemia-reperfusion group （I/R） and cyelophosphamide treatment group （T） was set up.Treatment group was given intraperitoneal injection of cyclophosphamide one hour after ischemia;the formation of reperfusion following cerebral ischemia two hours later;each group were observed with the duration of 24 hours,72 hours and 5 days. Expressions of GFAP in the hippocampus of rats among each group in different time slots as well as normal brain tissue were investigated by immunohistochemical method. Results The expression of GFAP in the hippoeampus increased gradually following the time of cerebral isehemia 5 days after ischemia-repufusion;The expression of GFAP emerged 24 hours later,increased 72 hours after and reached a peak 5 days later in I/R groups. There was no GFAP expression in the normal group or in the sham-operated group. Expressions of GFAP in the hippocampus decreased following the treatment of intraperitoneal injection of cyelophosphamide after cerebral ischemia（P〈0.05）. Conclusion The expression of GFAP in the hippoeampus following cerebral ischemia-reperfusion in 5 days in rats showed an positive correlation with the duration of isehemia. GFAP expression reduced after treatment with cyclophosphamide suggesting that cyclophosphamide has inhibiting effect on ischemia-induced activation of astrocytes and it may play an important role in the recovery after cerebral ischemiareperfusion injury.