The Role Of Hypoxia-inducible Factor-1α (HIF-1α) And Vascular Endotelial Growth Factor (VEGF) In Retina Ischemia-reperfusion Injury

Objective:Through make the common carotid artery ligation rat model of retinal ischemia-reperfusion by immunohistochemical assay in retinal HIF-1αand VEGF protein expression levels. Detected the rat electroretinogram (ERG) and HIF-1αand VEGF expression during each period, and observed of its retinal ischemia -reperfusion injury in rats. At the same time to observe the period of retinal ischemia-reperfusion injury in the histopathological changes.1,To study the expression of HIF-1αand its correlated cell factor VEGF in retinal which injuried by ischemia-reperfusion ,To research the effect of HIF-1αand VEGF in retinal's ischemia reperfusion injury.2,To study the relationship of HIF-1αand VEGF in rat's ischemia-reperfusion injuried retina.Method:1,The model of rat's retina ischemia-reperfusion was employed by ligation the left side common carotid artery.70 Spragne Dawley rats were divided in to two groups by random : the ischemia-reperfusion group, and the control group(sham operation group). Each group was divided into lh,6h,12h,24h,48h,72h,144h small groups according to the reperfusion time. each small group has 5 rats. each group was ligationed the left side common carotid artery for 60min,and loose the ligation, the right eye as the self control eye.2,Take 10 Spragne Dawley rats by random to carry ERG test, its result as the normal control to carry ERG test for different groups and stages. use the left eye/right eye's ERGa,bwave of ampultide ratio as the relative recovery ratio.3,Use immunohistochemical method to test the expression of HIF-1αand VEGF rotein in different stages of different groups . Carry the negative and opsitve matched control.4,Each stage of different groups carry histopathology examination.Result: 1,There was no significant discrepancy between left eye's and right eye's ERGaA and ERGbA in control group. After ligation the common carotid artery, the ERG aA, bA decreased rapidly. In ischemia-reperfusion group, the relative recovery ratio of ERGaA and ERGbA decreased gradually, it was the lowest level at 24 h after reperfusion injuried. Then it recoveried gradually by the extension of reperfusion time.2,There has significant changes of Histopathology in ischemia-reperfusion group. the lesion was the most at 24h,and no histological structure change in control group.3,There was no HIF-1αand VEGF protein expressed in control group's retinal.The protein of HIF-1αand VEGF can be detected feeble express at 6h,have a significant express at 12h,and reached the highest level at 24h,then desceased gradually by the extionsion of the reperfusion time.Conclusion:1,With the extension of ischemia-reperfusion time ,the retinal lesion gradually degree. The relative recovery ratio of ERGaA and ERGbA decreased to the lowest level at 24h after reperfusion injuried , it speculates that the the 24h group retinal was the most lesion.2,The protein of HIF-1αand VEGF express in the retinal ischemia-reperfusion injury group,may be related to the lesion of the retinal.3,There is a positive correlation between HIF-1αand VEGF during the expression of HIF-1αand VEGF protein in retinal's ischemia-reperfusion injury .4,HIF-1αwas activated when the retinal was under the ischemia-reperfusion injury,at the same time,induced VEGF expressed in retinal,which takes important role in retinal's ischemia-reperfusion injury,however the specific mechanism remains to be further study.