The Effect Of Rapamycin On MMP-9 Expression Level In Rat Ischemia/Reperfusion Injury

Objective To study the protective effects and the mechanism of rapamycin (RAPA) on ischemia-reperfusion-induced injury in retina of rat, and investigate the effect and mechanism of RAP A on metalloprotelnase-9 in rat retinal ischemia/reperfusion injury.Methods 81 healthy Wistar rats were used in the study. All of the rats were divided into three groups randomly:in normal (blank) control group, and in experimental group, each group was 27 rats. RIR was induced in control group and in experimental group Wistar rats by increasing intraocular pressure via an intra-cameral catheter. The experimental group rats underwent a intraperitoneal injection with rapamycin (2 mg/kg) 2 hours before retinal ischemia; and in the control group, saline water and dimethyl sulfoxide were injected correspondingly. The observation morphology of RGCs and the thickness of the inner retinal layers was measured by HE staining method before and 0, 6,12,24,and 48 hours after reperfusion. The levels of MMP-9 mRNA were analyzed by Realtime PCR assay. The levels of MMP-9 protein were analyzed by western-blotting assay.Results (1) In the early period of retinal ischemia-reperfusion injury, the edematous status was lighter than that of the control group, and less RGCs vacuolar phenomenon. (2)At 6 hours after reperfusion, the expression of MMP-9 mRNA began to increase and reached the peak at 24 hours after RIRI (the relative expression levels of mRNA and protein were 7.6±0.16 and 5.6±0.26, respectively). (3) RAPA declined the expression of MMP-9 mRNA and MMP-9 protein in experimental group, the difference between experimental group and control group was statistically significant (P<0.01), the difference between experimental group and experimental control group was statistically significant(P<0.01)Conclusion RAPA can protect the retina from ischemia-reperfusion injury. The down regulation of MMP-9 maybe involved in the mechanism of the protection...