The Expression And Significance Of Glucose-regulated Protein On Rats Retinal Excitotoxicity Injury

Objective:To evaluate the expression of GRP 78 on rat 's retina excitotoxicity injury induced by NMDA and investigate the role of endoplasmic reticulum stress(ERS)in excitotoxicity injury.Methods:42 clean healthy Wistar rats were randomly divided into three groups,normal control group including 6 rats,experimental control group including 6 rats and experimental group including 30 rats.The rats of normal control group received no treatment.2?1 of NMDA of concentration of 80mmol/L was intravtreal injectded into the one random eye of every rats of experimental group and same volume PBS was intravtreal injceted into the one random eye of experimental control group.Normal control group and the experimental group of rats were sacrificed at any point in time.The experimental rats were sacrificed randomly after modeling 2h,6h,12h,24h,48h.The rat's retina were HE stained and observed under light microscope,and the protein level of GRP78 were detected by immunohistochemistry;GRP78mRNA in rat's retina were detected by semi-quantitative Real-Time polymerase chain reaction(Real-Time RT-PCR).Results:1.HE staining:The structure of retina of normal control group and experimental control group was histologically well-defined,uniform instaining,and with regular cell shape.In experimental group,2h after injection,mild edema appeared in the nerve fiber layer(NFL)and retina ganglion cells(RGCs);retinal slightly thickened.6h after injection,retinal edema heavier than before 12h after injection,the NFL and RGCs were dropsical the most severely and the cell disorder than before.After modeling 24h,the dropsieal condition was alleviative,the number of retinal ganglion cells was reduced and retina become thin.After modeling 48h,ganglion cells significantly reduced and the retinal atrophy.2.Immunohistochemistry(IHC)results:The weak expression of GRP78 were seen in rat retina of normal control group and the experimental group,and are mainly located in the ganglion cell layer and inner nuclear layer.After modeling 2h GRP78 expression levels began to increase(P<0.05),continued to increase at 6h(P<0.05),peaked at 12h(P<0.05),gradually decreased at 24h,but still higher than the normal control group(P<0.05),the expression level of 48h compared with the normal group,no statistically significant(P>0.05).3.Semi-quantitative RT-PCR:The weak expression of GRP78mRNA was seen in rat retina of normal control group and the experimental group.After modeling 2h GRP78mRNA expression levels began to increase(P<0.05),and GRP78mRNA peaked at 12h(P<0.05),gradually decreased at 24h,and the expression level of 48h compared with the normal group,no statistically significant(P>0.05).Conclusion:1.The rats' retinal excitotocity injury model has been set up successfully.2.The expression of GRP78 in the retina excitotoxicity injury induced by NMD A increases and it may be involved in the pathogenesis of retinaexcitotoxic injury.3.The toxic effects of excitatory amino acids were reduced by interfering ERS,and then the optic nerve waas protected.