Effect Of Ligustrazine Pretreatment On Expression Of Heat Shock Protein70 In Rats' Ischemic-Reperfusion Injuried Retina

Objective To examine whether ligustrazine pretreatment can up-regulate the expression of heat shock protein70 in rats'ischemic-reperfusion injuried retina and further attenuate ischemic-reperfusion damage to rat's retina.Methods 60 anesthetized Sprague-dawley rats were randomly divided into 5 groups with 12 rats in each group: control group, ischemic-reperfusion group, ligustrazine pretreatment group, 5-min ischemic preconditioning group and ligustrazine combined with Actinomycin D group. Retinal ischemia lasting for 60 minutes was induced by increasing the intraocular pressure through infusion into the anterior chamber. The contents of retinal Superoxide dismutase and Malondialdehyde were measured at 24h following reperfusion. Additionally, expression of Heat Shock Protein 70 was detected immunohistochemically and the retinal ultra-structure were observed by transimission electron microscope at 1h, 24h, 168h following reperfusion. In retinal function aspect, electroretinogram was recorded before ischemia, during the course of ischemia and at 1h, 12h, 24h, 72h, 168h following reperfusion from both eyes. Meanwhile, the recovery rate of b and Ops waves were calculated (Recovery rate =waves of treated eye / contralateral eye *100%).Results In contrast to the ischemic-reperfusion group and ligustrazine combined ACTD group, ligustrazine pretreated rats and 5-min ischemic preconditioned rats showed significantly promotion in recovery rate of b waves and Ops waves. Retinal ultra-structural injury was relieved with the activity of retinal SOD increased, contents of MDA lowered and expression of HSP70 elevated significantly (P<0.05). The protein synthesis inhibitor ACTD can cancel the protective effect of ligustrazine pretreatment.Conclusions Similar with 5-min ischemic preconditioning, ligustrazine pretreatment can protect retina from ischemic reperfusion injury and abolishment of this protective effect by ACTD supports the hypothesis that expression of HSP70 may play a protective effect in ischemic-reperfusion injuried retina.