The Study On The Protective Effect Of Recombinant Human Erythropoietin(rhEPO) On The Retinal Ganglion Cells Of The Rat Which Retinal Ischemia Reperfusion Caused By Acutely Increased Intraocular Pressure

Objectives To establish the acute retinal ischemia-reperfusion rat animal model,to study the effect of recombinant human erythropoietin on the survival rate of the retinal ganglion cells and recovery of the visual function of the animal model and its'influence on the inducible nitric oxide synthase(iNOS) protein's expression.To discuss the possible function mechanism of rhEPO protective effect on the RGCs.To provide a new thought for clinic treatment of the optic nerve injury.Methods 1 Establishing acute retinal ischemia-reperfusion rat animal model,applying the fluorescence gold tracing technique to observe the survival rate of the RGCs and introducing the flash visual evoked potential method to look into the recovery of the visual function.2 Using the immunohistochemical means to examine the iNOS expression after the acute retinal ischemia-reperfusion and to explore the influence of rhEPO on the iNOS expression.Results 1 When rhEPO was used after the animal injuried 1d,4d,7d,14d,the survival rate of RGCs was individually inhenced from 89%,82%,52%,36%to 99%,94%,92%,52 %.2 After the acute retinal ischemia-reperfusion,the swing recovered to 71.89%of normal level in treatment group,the swing recovered to 40.86%of normal level in control group.Which indicate that rhEPO has a definite promoting function on the visual function in the case of the acute retinal ischemia-reperfusion.3 There was no iNOS postive cells in normal retina,but in the first day after the animal injuried,iNOS postive cells were distinctly manifolded,they were compressively distributed on the outer nuclear layer,inner nuclear layer and retinal ganglion cell layer of the rats' retina.In the fourth day after the animal injuried,iNOS expression were partly declined.But in the seventh day after the animal injuried,iNOS expression were partly increased,they were persisted untile the fourteenth day after the animal injuried.However,in rhEPO treatment group,iNOS expression were evidently lower than the control group,and the difference has notability (p＜0.05).Conclusions 1 rhEPO enhenced the survival rate of RGCs in the case of the acute retinal ischemia reperfuson and has a definite promoting function on the visual function.2 After the acute retinal ischemia-reperfusion,the upregulation of iNOS expression is the one of the main causes of apoptosis of the retinal neurons,and rhEPO inhabit its' iNOS expression.So functional mechanism of rhEPO on apoptosis of the retinal neurons after the acute retinal ischemia-reperfusion may lies in its' downregulation of iNOS expression.