Riboflavin-mediated Photooxidation In Photo Damage Of Lens Induced By LED

Objective: The purpose of this study is to investigate the photooxidation effect of light emitting diodes(LEDs)on lens.To study the mechanism of the photodamage on lens induced by LED.To explore the action spectrum of the photodamage on lens induced by LED and inform the protection strategy of it.Method:1.(1)LED was used to irradiate HLEB-3 cells and rats’ lens in vitro to establish the in vitro model.The morphological change of lens epithelial cells and lens of rats were observed with microscope.The apoptosis rate of human lens epithelial cells and the content of reactive oxygen species were detected by flow cytometry and ELISA.(2)The changes of rat lens were evaluated by direct ophthalmo-scope in vivo,the pathological morphology of rat lens were detected by HE staining.Evaluate the hydration of lens by dry wet weight difference/wet weight of lens tissue.2.The apoptosis rate of lens epithelial cells,the content of reactive oxygen species in cells and tissues,and the transparency of lens were compared by flow cytometry,ELISA and ESR.(2)ESR experiment verified that riboflavin in lens is the necessary photosensitive substance for LED light damage;The static and dynamic concentrations of riboflavin were measured by ELISA;ESR was used to detect the photoproduction of free radicals in aqueous humor,lens and different concentrations of riboflavin aqueous solution.(3)Using the connecter device and ESR,the characteristics of lens damage caused by LED light acting on aqueous humor were elucidated.3.(1)Spectrometer was used to measure the light spectrum of LED,and UV-visible spectrophotometer was used to measure the absorption spectrum of riboflavin aqueous.(2)In vivo and in vitro experiments were carried out to verify the influence of filtering out the above-mentioned action spectrum on lens LED light damage.Result:1.(1)LED irradiation could induce abnormal morphology of lens epithelial cells and decrease the transparency of lens tissue.Compared with the control group,the apoptosis rate and the level of reactive oxygen species in cells and tissues were significantly increased after LED light irradiation(P < 0.05).(2)Cortical fibers of rat lens were abnormal and turbid after LED light irradiation detected by ophthalmoscope and HE staining.The level of ROS,the apoptosis rate and tissue hydration degree were increased compared with the control group(P < 0.05).2.The dynamic riboflavin concentration in aqueous humor and lens epithelium under static and LED light irradiation was significantly higher than that in lens nucleus.The permeability of free riboflavin in lens epithelium and cortex was higher than that in nucleus.ESR showed that the aqueous humor,lens epithelium and cortex of rats could show free radical wave after LED light irradiation,but there was no free radical wave in nuclear tissue.He staining showed that the level of LED light damage in the lens tissue after riboflavin treatment was significantly deepened.(4)In vitro simulation experiments combined with ESR showed that led light could produce diffuse damage effect by acting on riboflavin in the aqueous solution around the crystal.3.(1)The absorption spectrum of riboflavin was coincided with the LED spectrum at 400nm-500 nm.(2)After filtering out the spectrum of 400nm-500 nm in LED,the apoptosis rate of LECs,the content of ROS,lens hydration were significantly decreased compared with the white LED irradiation group(P < 0.05),and the lens were also maintain the transparency.Conclusion: Direct irradiation of LED light can damage to cultured human lens epithelial cells and rat lens.The apoptosis rate of lens epithelial cells increased and the transparency of lens decreased;Continuous and intermittent irradiation with LED light can also cause damage to the lens in vivo.2.Riboflavin,as a endogenous substance in lens,is a necessary photosensitizer in LED photo oxidative damage of lens.The distribution of reactive oxygen species in the lens under LED light stimulation is determined by its hierarchical characteristics,which damage change of lens distributing located in the epithelium and superficial cortex.3.LED light can produce reactive oxygen species by irradiating riboflavin in aqueous humor.4.The400nm-500 nm band of white LED is the action spectrum which leads to the oxidative damage of lens.The oxidative damage of lens caused by LED light can be significantly reduced by filtering out the spectrum of this range.