An ultrastructural study on protection of mild hypothermia for rats' retinal pigment epithelium from ischemia and reperfusion injury

t: Objective: To explore if mild hypothermia protects rats' retinal pigment epithelium from ischemia and reperfusion injury by observing the ultrastructure of retinal pigment epithelium.Methods: 24 SD rats were randomly divided into 3 groups:the control group,the ischemia and reperfusion group and the ischemia and reperfusion group with mild hypothermia.In the experimental groups,intraocular pressure(IOP) was raised to occlude retinal and choroidal blood vessels to form retinal ischemia;afterwards IOP was lowered to normal level to allow reperfusion.The ultrastructure of retinal pigment epithelium of these 3 groups was observed by transmission electron microscope.Results: The microvilli and infold of plasmic membrane of basis of retinal pigment epithelium were a few and scattered,shortened so far as to be come off and lowered in the ischemia and reperfusion group,there were mainly impaired present in swelling mitochondrial,crista were fallen off and enlargment of endoplasmic reticula.However mild hypothermia could markedly abate the pathologic changes described above.Conclusion: Mild hypothermia could protect the retinal pigment epithelium from ischemia and reperfusion injury.