| Objective:1. The right cephalic artery of each rat was clipped to build model of retina ischemia-reperfusion. Investigated changes of morphological structure of each layer after retina ischemia-reperfusion injury, trends of B-cell leukemia/lymphoma-2and Bcl-2-associated X and the number of apoptosis in retina in the rats.2. To preliminarily explore the role of simvastatin on retina ischemia-reperfusion injury in a rat model, it can provide theoretical evidence for further therapy of ocular ischemia-reperfusion injury.Methods:1. Used the method of clipping cephalic artery of each rat. One hundred and sixty-five healthy adult male SD rats were randomly diveded into three groups using digital table method, normal control group(CON,55rats), ischemia-reperfusion model group(MOD,55rats) and the medicine of simvastatin group(SIM,55rats). Each group was divided into five points in time of4hours,8hours,16hours,24hours and48hours, and there were11rats in each point. The right cephalic artery of each rat was clipped in model group and simvastatin group, but it was exposed in control group.2. After4h,8h,16h,24h and48h, managements on control (CON) group, model group (MOD) and simvastatin group (SIM) were to take off the necks to death. Eyeball specimens of rats were respectively used for HE staining to detect changes of morphological structure of each layer in retina, immunohistochemical staining to detect Bcl-2and Bax protein expression levels, Real Time RT-PCR to detect Bcl-2and Bax mRNA expression levels by extracting of RNA of retina, and the method of Tunel to detect apoptosis of retinal layers.Results:1. HE staining results showed:The structure of each layer of retina in control group was not abnormal. At the time of8h, retina in model group became edematous. At16h, edema was aggravating, the number of RGCs was decreased, the thickness of INL of retina became thin. At24h, edema disappeared basically, the number of RGCs was continued to reduce, the thickness of INL became thinner. At48h, the retina got thin. At the time of8h and16h retinal tissue edema in simvastatin group relieved compared with model group. At16h,24h and48h in simvastatin group, the number of RGCs were reduced lower compared with model group, the changes of the thickness of INL of retinal were not obvious.2. Immunohistochemical results showed:Expression of Bcl-2protein in model group began to decline at4h, reached the lowest at24h, and the numbers were statistically significant with control group(P<0.05). Expression of Bcl-2protein in simvastatin group were higher than those in model group at each time point(P<0.05). The numbers were statistically significant at corresponding time point in each group(F4,8,16,24,48=8.079,9.005,9.904,35.563,8.810,P<0.05). However, expression of Bax protein in model group began to increased at4h, reached the highest at24h, and the numbers were statistically significant with control group(P<0.05). Expression of Bax protein in simvastatin group were lower than those in model group at each time point(P<0.05). The numbers were statistically significant at corresponding time point in each group (F4,8,16,24,48=16.601,13.525,10.303,25.849,13.805,P<0.05).3. Real Time RT-PCR results showed:Bcl-2mRNA in model group were lower than those in control group, and the differences were statistically significant(P<0.05). But Bcl-2mRNA in simvastatin group were higher than those in model group, the differences had statistical significance(P<0.05). The differences had statistical significance at corresponding time point in each group (F4,8,16,24,48=112.934,109.750,3534.800,112.428,128.140,P<0.05).And Bax mRNA in the model group were higher than those in control group, and the differences were statistically significant(P<0.05). However, Bax mRNA in simvastatin group were lower than those in model group, there were statistical significant differences(P<0.05).The differences had statistical significance at corresponding time point in each group (F4,8,16,24,48=74.115,54.504,81.271,243.743,97.163,P<0.05).4. Tunel results showed:apoptosis index (AI) of retina in model group began to increased at4h, reached the highest at24h, the numbers were statistically significant with control group(P<0.05). AI of retina in simvastatin group were lower than those in model group at each time point(P<0.05). The numbers were statistically significant at corresponding time point in each group (F4,8,16,24,48=87.096,232.245,575.564,389.205,771.658,P<0.05).Conclusions:1. It is succestful by using the method of clipping cephalic artery to establish the model of retina ischemia-reperfusion in rats in this study. In model group, the expression of Bcl-2reduced, the expression of Bax increased, the thickness of retinal became briefly edema, the number of RGCs were decreased, the thickness of INL got thinner, and the number of apoptotic cells were increased.2. In simvastatin group compared with model group, the expression of Bcl-2increased, the expression of Bax reduced, the changes of the thickness of retina were not obvious, the less number of RGCs were decreased, and the number of apoptotic cells were reduced.Hence, the changes of the proportion of Bcl-2and Bax play an important role in the process of the development of retina ischemia-reperfusion.3. Cell apoptosis induced by retinal ischemia-reperfusion may inhibit by simvastatin, which possibly adjusts the expression of apoptosis gene Bcl-2and Bax. It may provide a new way to prevent and treat retinal ischemia-reperfusion injury. |
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