Glutamine Induces Heat-shock Protein70 In Retinas Of Unstressed Rats

PURPOSE. To study the effects of glutamine(GLN) on the expression of inducible HSP70 in retinal cells of unstressed rats.METHODS.A total of 90 rats were randomly divided into three groups, normal control group including 10 rats, positive control group in which rats were treated with zinc sulfate including 10 rats, experimental group in which rats were treated with glutamine including 60 rats.10 rats were sacrificed at 1h,4h,6h,12h,24h,48h,72h randomly and respectively after glutamine intraperitoneal injection(0.75g/kg). The rats in positive control group were sacrificed at 12h after zinc sulfate intraperitoneal injection(24.6mg/Kg). Randomly choosed five rats'retinas of every 10 rats for western blot analysis to examine the induction of HSP70 and the rest five rats' retinas for mmunohistochemistry to localize HSP70.RESULT.The Western blots of proteins from the whole rat retinas after systemic administration of GLN show that there was weak immunoreactivity for HSP70 in retinas from the normal untreated control retinas. 1h after administration of GLN, a mild increase in immunoreactivity of HSP70 was noted in the retinas. A strong increase in immunoreactivity was detected in retinas treated with GLN for 4 h,and it persisted until 24h.There was a mild decrease of HSP70 expression in the 24h and 48h group and there was no significant difference in HSP70 expression between the two groups.The obviousely decrease of HSP70 expression occurred when injected GLN for 72h,but it was still stronger than the normal control retinas. Increased immunoreactivity of HSP70 was detected in cells of almost all layers of retinas by immunohistochemical staining after treatment with GLN while Hsp70 immunostaining was observed exclusively in the inner segment of photoreceptors,the outer limiting membrane layer and the outer nuclear layer (ONL) of the normal control rat retina. The result of the quantitative analysis of immunoreactive intensity of HSP70 in retina was similar to the result of Western blot.CONCLUSION 1. There was mild HSP70 expressed normal retina.2. HSP70 can be induced by glutamine intraperitoneal injection and the level of expression changed with time...