ABSTRACT
Objectivc To investigate the protective effect of simvastatin on retinal ganglion cells (RGC) after optic nerve crush (ONC).Methods Together 50 Kunming mice were randomly divided into normal group,sham group,ONC group and simvastatin protection group.The mice in the normal group were untreated,the sham group was treated with the exposure of the optic nerve without injury,the ONC group mice underwent ONC operation on the left eyes,followed by intravitreal administration of equilibrium solvent [50 mg · mL-1 ethanol plus 1 mol · L-1 NaOH,which were activated by 1 mol · L-1 HC1 (pH 7.2)],and the simvastatin protection group was intravitreally injected different concentrations of simvastatin (0.5 g · L-1,1.0 g · L-1,1.5 g · L-1) after ONC operation.Brn3a immunofluorescence staining,HE staining and toluidine blue staining were used to detect the apoptosis of RGC and pathological changes of optic nerve.Results On day 7 after operation,in the ONC group,the apoptosis of RGC was observed obviously,with the survival rate dropping to (35.1 ± 3.9) ％,and the thickness from the retinal ganglion cell layer to outer nuclear layer was decreased from (123.13 ± 1.04) μm to (97.48 ± 2.33) μm,which was significantly thinner than that in the control group (P ＜ 0.01);moreover,the fibrous bundle of optic nerve disappeared,and the neuroglial cells were clustered into groups,as well as the axons showed swelling and serious degeneration,but after intravitreal injection of 1.0 g · L-1 simvastatin,the survival rate of retinal ganglion cells increased to (76.3 ± 3.7) ％ (P ＜ 0.05),and the aforementioned thickness was increased to (111.39 ± 4.06) μm,which was statistically significant when compared with the ONC group (P ＜ 0.01).The degeneration of optic nerve was improved,and the structure of neuroglial cell axons and the nerve fibers became normal.Conclusion Simvastatin can reduce the optic nerve degeneration and improve the survival rote of retinal ganglion cells.