Objective: To explore the protective mechanism of simvastatin on retina ischemia-reperfusion injury in a rat model.
Methods: It was a experiment study.One hundred and sixty-five adult male SD rats were randomly divided into three groups using digital table method, normal control group (CON, 55 rats), ischemia-reperfusion model group (MOD, 55 rats) and the medicine of simvastatin group (SIM, 55 rats).Each group was divided into five points in time of 4 hours, 8 hours, 16 hours, 24 hours and 48 hours, and there were 11 rats 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. Expression of Bcl-2 and Bax protein were determined by the immunohistochemical method, the number of cell apoptosis in retina were examined by the TUNEL method and express of Bcl-2 and Bax mRNA were measured by the real-time PCR method. The expression of proteins and mRNAs of Bcl-2 and Bax and also apoptosis of the rat retinas in each group at corresponding time point are compared using single factor analysis of variance and LSD-t test.
Results: Expression of Bcl-2 protein in model group began to decline at 4 h, reached the lowest at 24 h, with the data of (0.192 ± 0.011), (0.192 ± 0.015) , (0.189 ± 0.015), (0.183 ± 0.012) and (0.187 ± 0.010) .Expression of Bcl-2 protein in simvastatin group were higher than model group at each time point, with the information of (0.208 ± 0.011), (0.220 ± 0.011) , (0.221 ± 0.014), (0.228 ± 0.007) and (0.206 ± 0.015). The numbers were statistically significant at corresponding time point in each group (F(4, 8, 16, 24, 48) = 8.079, 9.005, 9.904, 35.563, 8.810, P < 0.05). Expression of Bax protein in model group began to increased at 4 h, reached the highest at 24 h, with the data of (0.255 ± 0.010), (0.261 ± 0.033), (0.276 ± 0.025), (0.324 ± 0.037) and (0.234 ± 0.018). Expression of Bax protein in simvastatin group were lower than model group at each time point, with the information of (0.222 ± 0.012), (0.219 ± 0.017), (0.223 ± 0.008), (0.232 ± 0.021) and (0.214 ± 0.008). The numbers were statistically significant at corresponding time point in each group (F(4, 8, 16, 24, 48) = 16.601, 13.525, 10.303, 25.849, 13.805, P < 0.05). AI of retina in model group began to increased at 4 h, reached the highest at 24 h, with the data of (11.771 ± 0.722), (13.705 ± 0.512), (15.533 ± 0.370), (21.210 ± 1.221) and (17.660 ± 0.414). AI of retina in simvastatin group were lower than model group at each time point, with the information of (9.061 ± 0.289), (11.717 ± 0.565), (13.506 ± 0.541), (16.586 ± 0.488) and (14.428 ± 0.559). The numbers were statistically significant at corresponding time point in each group (F(4, 8, 16, 24, 48) = 87.096, 232.245, 575.564, 389.205, 771.658, P < 0.05). Bcl-2 mRNA in model group were lower than in control group at each time point, with the data of (0.360 ± 0.017), (0.232 ± 0.066), (0.314 ± 0.012), (0.179 ± 0.019) and (0.357 ± 0.084). But Bcl-2 mRNA in simvastatin group were higher than those in model group, with the information of (1.718 ± 0.247), (1.981 ± 0.317), (1.309 ± 0.031), (1.289 ± 0.209) and (0.684 ± 0.071). The differences had statistical significance at corresponding time point in each group (F(4, 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 at each time point, with the data of (2.140 ± 0.288), (3.189 ± 0.492), (2.896 ± 0.466), (2.392 ± 0.119) and (1.789 ± 0.169). However, Bax mRNA in simvastatin group were lower than those in model group, with the information of (0.658 ± 0.197), (1.746 ± 0.315), (0.670 ± 0.221), (0.952 ± 0.164) and (0.575 ± 0.174). The differences had statistical significance at corresponding time point in each group (F(4, 8, 16, 24, 48) = 74.115, 54.504, 81.271, 243.743, 97.163, P < 0.05).
Conclusions: Simvastatin has protective effects on retinal ischemia reperfusion injury, and the mechanism is closely related to inhibiting retinal cell apoptosis by adjusting the express of Bcl-2 and Bax.