Effects Of Recombinant Human Erythropoietin On The Rat Retina After The Eye Contusion

·Purpose:Ocular contusion is a common ocular injury.There will be no sequelae after curement in case of a light injury but it can lead to blindness in case of serious injury.It is one of the major reasons for blindness.Expectant treatment is the first choice in clinic,but there are no specific medicines now.Data show that erythropoietin(EPO) can protect the nerve cells such as the retinal ganglia cells(RGCs) and the photoreceptor cells inhibit cells and so on by inhibiting apoptosis,thus is expected to be the new target medicine for neuroprotection.In this experiment molecules of erythropoietin(EPO) with neurotrophic activity were being evaluated for treating ocular contusion in rat animal models by detecting the mRNA expressing of fas and caspase-3,and the electrophysiology of the rat Eyes,including flash electroretinogram(FERG) and flash visual evoked potentials(FVEP),were investigated,which shows the protective effect of rhEPO in the rat retina after the eye contusion made by modified Allen's Failing strike.Then a new idea of treating ocular contusion is put forward.·Methods:1.36 male Sprague-Dawley(SD) rats were randomly divided to 3 groups:normal control group(group A,n=4),EPO administrated group(group B,n=16) and the isotonic Na chloride group(group C,n=16).In all groups the left eyes of the rats were targeted for experiment.Group A were killed after 7 days,and the retina were peeled. All the left eyes of group B and C were made into the contusion model by modified Allen's failing strike.The rhEPO 5U was injected into the corporis vitre of group B's left eyes after striking immediately.The same dose of isotonic Na chloride was injected into the group C's left eyes after striking immediately.They were killed on the 1st,4th,7th,and 14th day respectively,and the retina were peeled.The fas mRNA and caspase-3 mRNA were examined by Real Time PCR.The differences were analyzed.2.12 male SD rats were randomly divided into 2 groups:EPO administrated group(group A,n=6) and the isotonic Na chloride group(group B,n=6).They were handled by the same method as before.FERG and FVEP were detected on 1 day before and on the 1st,4th,7th and 14th days after contusion respectively.·Results:1.Expression of fas and caspase-3 mRNA of group B and C is higher than that of and reached the highest level group A on the 1st day(P＜0.05),therefore reduced gradually and got close to normal level(the level of group A,P＞0.05) on the 14th day.The change trends of fas and caspase-3 mRNA are basically the same.Comparing at each time point,group B's expression of fas and caspase-3 mRNA are obviously lower than those of group C(P＜0.05).2.The amplitude values of FERG-b wave and that of FVEP-P₁₀₀ wave had no significant difference between the control group and the EPO group before ocular contusion(P＞0.05).The amplitude of FERG-b wave and the amplitude of FVEP-P₁₀₀ wave of both groups dropped down to the lowest level on day 1 after contusion and continued to recover thereafter.Comparing the EPO group and the control group,the amplitude values of FERG-b wave and that of FVEP-P₁₀₀ wave had no significant difference on day 1 after contusion,the difference is observed on day 4(P＜0.01), thereafter the difference keeps on increasing.The amplitude values of FERG-b wave and that of FVEP-P₁₀₀ wave of the EPO group are higher than that of the control group at each time point since day 4(P＜0.01 ) and reach the biggest on day 14.At the end of the experiment,the amplitude values of FERG-b wave and that of FVEP-P₁₀₀ wave of the EPO group are obviously higher than those of the control group(P＜0.01),getting close to the levels before modeling(P＞0.05).·Conclusion:1.RhEPO has an important role in reducing the expression of fas and caspase-3 in rats' retina after contusion,and inhibiting the apoptosis of retinal cells.Therefore it can inhibit injures to retina by contusion.2.Fas and caspase-3 are in the same change trends after retinal bruise.3.RhEPO can significantly improve the amplitude of FERG-b wave and FVEP-P₁₀₀ wave after ocular contusion.This indicates that EPO has the potential to be an optimal neuroprotective agent.