Preliminary Study On The Influence Of LED Light On Rat's Lens

Objective : To observe the oxidative damage indexes(superoxide dismutase,glutathione peroxidase,malondialdehyde)in SD rats' lens which were irradiated by different intensities of white LED light after a certain period of time.Evaluate role of oxidative damage in light induced damage of ocular lens.Discuss the threshold range of white LED light damage on the antioxidant system in ocular lens of SD rat.Methods:SD rats aged 6 weeks,no limitation with sex,the rats were divided into control group,light group,300 lux 500 lux light group,1000 lux illumination,1500 lux group by using a random number table method,each with 20.The control group(Laboratory under natural light illumination,the environmental illumination was about 20 lux)and other groups were given LED light irradiation of 300,500,1000,1500 lux correspondingly(color temperature was 4500K)for 5 days,8 hours a day(8:00 to d16:00 a.m.p.m.).the inside temperature of LED light box was kept between 20?-23?.Lens and anterior capsule of lens were taken after the irradiation.We used TUNEL stain to observe the apoptosis of lens epithelial cells and calculated the apoptosis rate.Compared the level of superoxide dismutase(SOD),glutathione peroxidase(GSH-Px)and malonaldehyde(MDA)by biochemistry analyze and kits of SOD,GSH-Px and MDA.Results: The results of TUNEL stain and the apoptosis rate of LECs showed that:control group,300 lux group,500 lux group,1000 lux and 1500 lux group,the apoptosis rate of lens epithelial cell increased with the raise of intensity of LED light,with a statistically significant difference among the groups(P < 0.05).SOD,GSH-Px,MDA test results: SOD and GSH-Px content in the lens of the control group,500 lux group,1000 lux group and 1500 lux group decreased gradually and1500 lux group was the lowest.There were statistically significant differences among the groups(P < 0.05).SOD and GSH-Px content in the lens of 300 lux group were higher than the other groups,the difference was statistically significant(P < 0.05).The MDA content of control group,500 lux group,1000 lux group,1500 lux group increased gradually.MDA content of 1500 lux group was the highest,with statistically significant differences among the groups(P < 0.05).Furthermore,thedifference between 300 lux group and the control group was not significant(P >0.05).Conclusion:LED illumination can cause damage to lens in certain in cytology level(lens epithelial cell apoptosis),and its damage level is positively correlated with the illuminance intensity.And more than 500 lux light LED(color temperature is 4500K)can lead the increasing of lipid peroxidation(MDA)in rat lens in vivo.Levels of antioxidant enzymes(SOD,GSH-Px)content decreased consistently.Therefore,in LED light environment,the environmental illumination higher than 500 lux(the color temperature is 4500K)has potential light biohazard on ocular lens,environment illumination lower than 300 lux(color temperature is 4500K)is relatively safe for the lens.