Glutamine Induces HSP70on Retinal Excitotoxicity Injury In The Rat

PURPOSE. To observe the effects of glutamine (GLN) on the expression of HSP70in the rat’s retina excitotoxicity injury induced by NMDA.METHODS.A total of70rats were randomly divided into three groups, normal control group including10rats, blank control group including10rats, experimental group in which rats were treated with glutamine including50rats. The rats of normal control group received no treatment.2μ1of NMDA of concentration of80nmol/1was intravtreal injected into the one random eye of every animal of experimental group and blank control group.After two days, the rats in experimental group were intraperitoneal injected with glutamine (0.75g/kg) and10rats were sacrificed at lh,4h,8h,12h,24h randomly and respectively after glutamine administration. The rats in normal control group and blank control group were sacrificed at1h. The rats’retina were HE stained and observed under light microscope, and the expression level of HSP70were detected by immunohistochemistry and Western blot analysis.RESULT. HE staining show the structure of retina of normal control group was histologically well-defined, uniform in staining, and with regular cell shape. In blank control group and experimental group, the retina ganglion cells (RGCs) with striking chromatin condensation were loosely arranged and fewer RGCs were found in the retina that became atrophic and thinner. The Western blot analysis showed there was slight expression of HSP70in normal control group and blank control group retinas. The expression of HSP70was observed increase at the lth hour after being injected with GLN, a strong increase was detected at4th hour, and reached the peak at the8th hour; until12th hour. There was a mild decrease of HSP70expression in the24th hour, but it was still stronger than the control retinas. The expression of HSP70was detected in cells of almost all layers of retinas by immunohistochemical staining after GLN administration. Compares with the experimental group, Hsp70immunostaining was only observed in the inner segment of photoreceptors, the outer limiting membrane layer and the outer nuclear layer (ONL) of the normal control and the blank control group rat retina. The result of the quantitative analysis of immunoreactive intensity of HSP70in retina was similar to the result of Western blot.CONCLUSION 1.The rat’s retina excitotoxicity injury model has been set up successfully.2. There was slight HSP70expressed in normal retina.3. HSP70can be induced by glutamine intraperitoneal injection in the retina excitotoxicity injury and the level of expression changed with time.