| Objective: To observe the morphology change, the content of malondialdehyde (MDA), the activity of superoxide dismutase (SOD), and the photoreceptor apoptosis in the retina of rabbit which suffered the ocular contusive injury and how about their change after use vitamin C protect.Methods: 55 New Zealand white rabbits (110 eyes) was randomly divided into three groups: The control group include 5 rabbits; Model A group and Model B group, each include 25New Zealand white rabbits. Model of ocular contusive injury was induced by a 2.9J energy contusion caused by a free falling iron bar hitting the cornea. Model B group was given vitamin C 250mg/kg through the vein right after the ocular injury, Retreated every 24h last for 3d. Using air embolism method to kill the control group in a lump and respectively and randomly kill 5 model A group and model B group at the time of 4h,1d,3d,7d,14d after ocular contusion. Colorimetry was used to measure the content of MDA, the activity of SOD, and the apoptosis of photoreceptor cell of each group in the retinal respectively. TDT-mediated biotin-dUTP nick end labeling (TUNEL) staining technique was used to measure the apoptosis of photoreceptor cell in the control group and in the A,B group 3d after ocular contusion. The morphologic changes of retinal were observed by light microscope. Results:1. HE stain indicated: In the control group the structure of retina arranges neatly. After ocular contusion, photorecepter outer segment were disruptured and at 1d edema was observed in the outer nuclear layer and compare with group B,group A is severity . Sparse nuclear at 3d, marked sparse nuclear at 14d were observe in the out nuclear layer. Compare with the thickness of out nuclear layer model A group was thinner than model B group at 7d and 14d.2. Very few apoptosis cells in normal control rabbit retina. At the time of 3d after ocular contusion, a lot of apoptosis cells can be found, in the out nuclear layer, thereinto the apoptosis index in model B group is less than that of model A group (P<0.05). 1. The content of MDA in the retinal of normal control group is low, after ocular contusion it began to increase at 4h and peaked at 3d,then gradually decreased and it is still higher than the normal at 14d in the group A. The content of MDA in model B group is lower than that of model A group at 3d, 7d after ocular contusion (P<0.05) and at 14d after ocular contusion it has no remarkable difference between the two group.4. At the time of 4h after ocular contusion the activity of SOD in the retina of model A and model B group is marked higher than that of the normal control group. At the time of 3d and 7d after ocular contusion the SOD activity in the retina of rabbit is marked lower than normal, and model B group's is higher than that of model A group. At the time of 14d the SOD activity in retina of both model A and model B group is near normal.Conclusions:1. The ocular contusion would lead to marked oxidative injury and the apoptosis of retinal photoreceptor cells,2. Vitamin C can protect and repair the retinal antioxidative system relieving the oxidative injury and reduce the apoptosis of retinal photoreceptor cells and protect the structure of retina after ocular contusion. |
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