Protective Effect Of α-Lipoic Acid Against Light-induced Retinal Damage In Mouse

objective To investigate the protective effect ofα-Lipoic acid onretinal damage in mouse . Methods: 42 BALB/C mouse were randomlyseparated into 4 groups: normal control, model control, drug-treatmentgroup(Group1:throughout operation,Group2:after operation). The mice exceptnormal control Group were exposed to intermittent white light in a trunk with12h dark adaptation and 12h light exposion at the light power of 21400±1600lx and the temperature between 25～29 degrees. The total exposed time is36h.The drug-treatment group were givenα-Lipoic acid via intraperitonealinjection with dose of 100mg/kg..The mice were respectively killed after 7 and14 days, the eyes were removed and were processed to paraffin section formicroscopy and TUNEL staining.. Then the morphological changes wereobserved and analyzed with optical microscope. the thickness of the outernuclear layer (ONL thickness) were measured. And we count the number ofapoptotic photoreceptors to compare the effect ofα-Lipoic acid onlight-damage of retina. The mean and Standard deviation were calculatedand analysed with analysis of variance. Results compared with themodel-control group, the mice of drug-treatment group had more clearlydemarcated retina structure and more ordered cells, The outer nuclearlayer retinal Cells and the photoreceptor cells were swelling but hadnormal morphology. We found that the ONL thickness of the mice ofnormal control group was 41.62±0.77um;and the ONL thickness of themice of model control group was 30.51±0.73um for 7 days, and20.04±0.52um for 14 days; and in the drug-treatment group, the ONLthickness was 40.52±0.80um in group C1 for 7 days,and 41.43±0.72um for 14days; in group C2, the ONL thickness was 31.70±0.70 um for 7 days, and38.92±1.43 um for 14 days, which was significantly (P<0.001) higher than those of the rats of model control group. TUNEL assay shows large amount ofTUNEL positive cells in ONL in the model control, and the number ofTUNEL positive cells in the treatment group were reduced. Theapoptosis index, AI of the mice of normal control group was less than one;and the AI of the mice of model control group was 15.44±1.72; and in thegroup C1, 7.23±0.65; in group C2, 7.48±0.88.The AI of the drug-treatmentgroup was significantly lower than the model control group. The statisticsshow that the thickness of ONL and AI had statisticalsignificance between the groups. ConclusioConclusion in the experimentconditions, the effect ofα-Lipoic acid on retina light damage wassignificant, which can protect and rescue the retina and inhibit pathologicalcells apoptosis after retinal photochemical damage.