缺血预处理对大鼠视网膜缺血再灌注损伤保护作用

目的：探讨缺血预处理是否对视网膜缺血再灌注损伤有保护作用及其机理，方法：利用前房灌注生理盐水形成高眼压的视网膜缺血再灌注损伤的动物模型，视网膜缺血时间为1h分别于缺血前30min、24h或72h对大鼠一只眼5min短暂缺血即预处理，24h或72h后行视网膜电图（ERG）、电镜、光镜、丙二醛（MDA）及热休克蛋白70（HSP70）检测，或者一侧眼行5min假处理，24h后行1h缺血，24h或72h再行上述检测，所有对侧眼不作处理作对照，结果：与假处理相相比，缺血前24、72h进行预处理后的大鼠视网膜光镜、电镜表现损害明显减轻，ERGb波明显恢复（P＜0．01），MDA含量降低（P＜0．01）,缺血前30min预处理的视网膜表现严重的损害，ERGb波几安全消失，结论：缺血预处理对视网膜缺血再灌注损伤有保护作用，且有一定时限性。

Ischemia preconditioning protects against retinal ischemia reperfusion injury in rats

Objective To examine whether ischemia preconditioning (IPC) can decrease ischemia reperfusion(I/R) injury in retina and investigate the mechanism. Methods Retinal ischemia was induced in SD rats by increasing the intraocular pressure to 14.63kPa for 60 minutes via cannulation into the anterior chamber. Retinal ischemia for 5 minutes constituted the preconditioning stimulus. Rats first underwent IPC and 60 minutes of ische mia 30 minutes, 24 or 72 hours later or they underwent a 5 minute sham PC and 60 minutes of ischemia 24 hours later. Their electroretinography(ERG), Light microscopy(LM),transmission electron microscopy (EM) and the expression of heat shock protein 70(HSP70) were observed and the content of malandialdehyde(MDA) in rat retinas were measured 24 or 72 hours later after 60 minutes ischemia.Results Ischemia induced histologic damage was completely prevented when IPC was performed 24 or 72 hours (but not 30 minutes) before ischemia. In contrast to the sham PC group, the amplitudes had complete recovery of b waves with preischemia basline amplitudes ( P <0.01),and the content of MDA was significantly decreased ( P <0.01).Conclusion IPC provides protection against retinal I/R injury just during limited period of time.