Protective effects of geranylgeranylacetone on rat retinal ischemia/reperfusion injury / 中华实验眼科杂志

ABSTRACT

Background Retinal ischemia/reperfusion injury is a common pathological process in ophthalmology.It can cause permanent visual impairment.The prevention and treatment of retinal ischemia/reperfusion injury is one of the focus topics at home and abroad up to now.Objective Present study was to evaluate the protective effects of geranylgeranylacetone(GGA)on retinal ischemia/reperfusion injury.Methods The retinal ischemia/reperfusion models were established in 40 SD rats by the infusion of normal saline solution into the anterior ehamber to elevate the intraoeular pressure for 1 hour and then remove the process.GGA of 2 ml (800 ms/kg)was intragastrieally administered in 20 model rats as GGA group,and the equal volume of normal saline solution was used at the same way in other 20 models as model group.Four normal matched SD rats were served as normal control group.The histological changes of retina in 6,24,48,72 hours after modeling was examined by hematoxylin-eosin staining under the light microscope.and the expression of heat shock protein 70(HSP70)and caspase-3 in retina at the time points mentioned above was detected by immunohistochemistry.Results The edema of cornea and retina of rats appeared in 1 hour and peaked in 24 hours after modeling.In 72 hours after modeling,the edema was alleviated but the disorder of retina structure was found in model group.However,although the pathological change process was similar to that of model group,the damage of retina tissue was milder in the rats of GGA group under the light microscope.HSP70 and caspase-3 were absent in the retina of normal rats.But。The expression of HSP70 in retinal ganglion cells(RGCs)was found in 6 hours after modeling,reached peak in 24 hours and declined after that in model group.The numbers of positive cells for HSP70 in retina was significantly increased in various time points in GGA group,showing statistically significant differences between model group and GGA group(P<0.05).In model group,a few of caspase-3 positive cells were found 6 hours after reperfusion and increased gradually until reaching the peak 24 hours and then decreased gradually 48 hours later.Few caspase-3 positive cells were found 72 hour8 after reperfusion.The numbers of positive cells for caspase-3 decreased in GGA group compared with model group during the experimental duration with the considerable difference between these two groups(P<0.05).Conclusion GGA could protect RGCs against isehemia/reperfusion injury by upregulating the expression of HSP70 and downregulating the expression of caspase-3 in retina.