ABSTRACT
PURPOSE: To examine light emitting diode (LED)-induced retinal photochemical damage and assess the protective performance of blue light-shielding films with different shielding rates in Sprague-Dawley rats (SD rats). METHODS: SD rats were randomly divided into five groups: blank control (group I), white LED illumination (group II), and white LED illumination combined with shielding of blue light of wavelength 440 nm at 40%, 60%, and 80% (groups III, IV, and V). The illumination was 200 lux. All animals underwent electroretinography (ERG), hematoxylin-eosin (H&E) staining, immunohistochemical (IHC) staining, and transmission electron microscopy (TEM) observation after 14 days of dark-adaptation before illumination, after 14 days of cyclic illumination, and after 14 days of darkness for recovery following illumination. RESULTS: ERG showed retinal functional loss after LED light exposure. However, retinal cell function was partly recovered after a further 2 weeks of dark adaptation. H&E staining and TEM revealed increases in photoreceptor cell death after illumination. IHC staining demonstrated that oxidative stress was associated with retinal injury. Although retinal light injury was discovered in the LED light-exposure groups, shielding 60% of blue light of wavelength 440 nm (bandwidth 20 nm) protected retinas. CONCLUSIONS: Cyclic illumination of low light intensity (200 lux) for 14 days produced retinal degeneration; shielding 60% of blue light may protect retinas from light damage. TRANSLATIONAL RELEVANCE: This study found the effective shielding rate that could protect retinas from light damage when shielding specific narrow-band harmful blue light; thus providing a more normative method for protecting eyes from blue light hazard.
ABSTRACT
@#AIM: To investigate the mechanism of Delphinidin(Dp)in protecting retinal against light induced oxidative damage.<p>METHODS: All 661W photosensitive cells were treated with 2 000Lx light(48h)and/or different concentrations of Dp(5, 10, 20μmol/L, 24h). Cell activity, intracellular LDH activity, TBARS content and antioxidant enzymes(SOD, GSH-Px, GST)activity were determined respectively. After the healthy SD rats were treated with 3 000 Lx light(24h)and/or Dp \〖100mg/(kg·d)for 4wk\〗, then changes in retinal tissue structure were observed and fluctuations in oxidative stress index(SOD, GSH-Px, GST)were determined.<p>RESULTS: The results of <i>in vitro</i> experiments showed that the cell activity was significantly decreased after irradiation, the LDH activity and TBARS content were increased, and the activity of antioxidant enzyme system were decreased. However, Dp treatment could increase cell viability, decrease LDH activity and TBARS content, and increase the activity of antioxidant enzyme system. <i>In vivo</i> experiments showed that Dp can protect the structural integrity of retina, reduce the content of TBARS in retinal tissue, and increase the activity of SOD, GSH-Px and GST.<p>CONCLUSION: Dp may protect retinal against Photochemical factors -induced oxidative damage by regulating the oxidation-antioxidant system.
