An Ultrastructural Study on Protection of Mild Hypothermia for Rat's Retina from Ischemia and Reperfusion Injury

Objective To know if mild hypothermia protects rat's retina from ischemia and reperfusion injury by observing the ultrastructure of retina. Methods 24 SD rats were randomly grouped into 3 groups:the control group,the ischemia and reperfusion group,and the ischemia and reperfusion group with mild hypothermia. In the experiment 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 retina of these 3 groups was observed. Results The pathologic changes of rat's retina after ischemia and reperfusion injury were mainly concentrated in visual cells and ganglion cells. The membrane discs of visual cells were swollen and disordered,mitochondria in the inner segment were partly swollen. Most ganglion cells were edematous,whose cytoplasm was thinly stained. The mitochondria were swollen and vacuolated,both smooth and rough endoplasmic reticula dilated; and some ganglion cells even ruptured. However,mild hypothermia could markedly abate the pathologic changes described above. Conclusion Mild hypothermia could protect the retina from ischemia and reperfusion injury.\;