Protective effect of ischemic preconditioning on rat retina with sustaining ischemia / 中国病理生理杂志

ABSTRACT

AIM: To observe the effect of ischemic preconditioning (IPC) on the subsequent permanent ischemic rat retina. METHODS: A model of two-vessel occlusion (2VO) was used to give an ischemic insult to rat retina. Bilateral carotid arteries were occluded directly in the simple ischemic groups. A procedure of double 2 min ischemia- 3 min reperfusion was applied to IPC groups before their carotid arteries were occluded. Experimental control groups received the same operation except that their exposed vessels were not occluded. Other 6 normal rats served as immunohistochemical controls. Eyeballs were taken out after being subjected to 1, 3 and 7 days of ischemia. The morphometry of retina was measured by stereologic methods. The apoptosis during the retinal ischemia was detected by TUNEL. Immunohistochemistry staining was used for the localization of bcl-2 in retina. RESULTS: In IPC groups, the thickness of retina was thinner than that in simple ischemic groups. The apoptosis was less when compared with the simple ischemic groups at the same ischemic time. The apoptotic cells show only in INL and the apoptosis of RGCs was not appeared until 7 days postischemia. There was no significant difference of the numerical density of RGCs at the different time after the operation. The bcl-2 immunoreactivity was weaker than that of the simple ischemic groups too. CONCLUSION: IPC reduced the injury caused by ischemia in retina, showing a protective effect.