Study On Retinal Ischemia-reperfusion Damage In Experimental Ocular Hypertension Rats And The Expression Of P75

Objective : To establish a new animal model of ocular hypertension and observe the development process of retinal injury in ischemia - reperfusion state and investigate the protective effect of compound injection salvia in retinal ischemia reperfusion (RIR).To make sure apoptosis occur in retina and detect the expressin of the low-affinity neurotrophin receptor p75 in RIR .Method : 74 Sprague-Dawley rats were devided into five groups at random , containing cornia damaged group, ischemia group,ischemia-reperfusion group, salvia miltiorrhiza protect group and normal saline control group.60 of 60 rats subjected to 90 minutes of pressure-induced ischemia, then fixed for light and electron microscopy with reperfusion after 1,4,12 hours, and 1 or 3 days from the time ocular ischemia was relaxed. p75 was examined in the retina by immunohistochemical at light level, result : Neuroganglion fibrous layer showed vacuolation degeneration when ocular hypertension was maintained to 90 min .the ganglion cells of retina showed that the karyltheca crimpled the karyotin agglomerated.the mitochondrion was vacuocated and the membranous disc of outer segment was damaged .The longer had ischemia-reperfusion continued, the more serious was the reperfusion injury .The histopathologic damage of retina in compound injection salvia group were not severe than that in the control group .The p75 was detected in the retinal ganglion cells , inner and out nuclear layer. During the time after the reperfusion started, especially after more than 12 hours, apoptotic signs became obvious and extended from the inner to the outer retina. These apoptotic findings could be seen with electron microscopy. By 3 days after the reperfusion, necrotic cells in the ganglion cell layer, and the inner and outer nuclear layer became more prominent thanapoptotic cells..Conclusion :RIR can make serious damage to retinal histopathology and ultrastructure. . mainline of compound injection salvia miltiorrhiza may be effected on protection from retinal damage induced by RIR. The low affinity neurotrophin receptor p75 seems to be involved in apoptosis after RIR . These results may provide a baseline for therapeutic strategy and the prognosis of ischemia-reperfusion injury in the retina.