【摘要】 目的　探讨大鼠局灶性脑缺血再灌注后血小板活化因子 (PAF)受体基因的表达变化规律及其机制。方法　应用RT PCR技术检测大脑中动脉 (MCA)线栓闭塞再通后不同时相MCA供血区皮质PAF受体基因的表达 ,同时用放免法测定对应PAF值。结果　单纯缺血 90min时 ,缺血区皮质PAF受体mRNA含量并无显著变化 ,密度比值为 0 92± 0 13;再灌注 6h明显降低 (0 77± 0 0 8) ,48h最低 (0 5 4± 0 10 ) ,随后逐渐回升 ;再灌注第 6天时与假手术对照组比较无显著差异。对应时相缺血区皮质PAF值 (pg/g) ,单纯缺血组为 2 80 2± 374,再灌注 12h最高峰 ,2 4h降至对照组水平 (75 2±16 3)。结论　脑缺血再灌注可致PAF受体基因表达异常 ,推测与内源性PAF水平升高有关。更多还原

【Abstract】 Objective To study the regularity and mechanisms of expression of platelet-activating factor receptor after rat focal ischemic middle cerebral artery occlusion/reperfusion.Methods 60 mature Wistar rats were randomly divided into twelve groups: sham-operated conrtol group, simple ischemia group, 6-hour (6 h), 12 h, 18 h, 24 h, 48 h, 3-day(3 d), 4 d, 5 d, 6 d, 7 d reperfusion groups. After the right middle cerebral artery occluded, the rats were suffered from ischemia for 90 minutes, then reperfusion was allowed for different time as mentioned above before decapitation. In sham-operated control rats, the thread inserted was only 9 millimeter long.Reverse transcription polymerase chain reaction(PCR) and radioimmunoassay were applied to evaluate the PAF receptor messenger RNA(mRNA) expression and PAF levels in rat ischemic brain tissue, respectively.Results RT-PCR analysis revealed that PAF receptor mRNA is the most abundant in rat brain of sham-control operated group. However, following ischemia-reperfusion, the levels of PAF receptor mRNA progressingly decreased untill 48 h reperfusion, then returned to sham-control group’s levels gradually. Compared with the control group’s, the PAF concentrations of simple ischemia and 6 h, 12 h, 24 h reperfusion group were significantly higher than that of any other groups. The PAF levels returned to basal values at 24 h.Conclusion These results indicate that PAF receptor gene expression may be subjected to down-regulation after focal cerebral ischemia and relative to increase of endogenous PAF concentrations.更多还原