The Effect of Light-Emitting Diode and Electrodeless Light Irradiation on the Morphology and Thickness of Guinea Pig Retina

Abstract

Background: The widespread use of light-emitting diode (LED) lamp has raised concerns about their potential health effects. This study was designed to explore the effects of light-emitting diode (LED) and electrodeless light on the morphology and thickness of guinea pig retinas. Methods: Guinea pigs were randomly divided into three groups: normal control, LED lamp, and electrodeless lamp. The guinea pigs in the normal control group were exposed to natural light, while those in the other two groups were exposed to LED light (wavelength: 450–460 nm) and electrodeless light (frequency: 220–200 mHz) for 8 hours daily, respectively. After 5 days, morphological changes of retinal were assessed using hematoxylin-eosin staining. Retinal cell apoptosis was evaluated through TdT-mediated dUTP nick-end labeling (TUNEL) staining. Levels of apoptosis-related factors and heat shock protein 70 (HSP70) in retinal cells were analyzed by Western blot. Results: In the normal control group, guinea pigs exhibited distinct inner structures and outer nuclear layers with well-defined boundaries and organized inner and outer retinal segments. However, the retinal structure was unclear in the LED lamp and electrodeless lamp groups, and the inner layer was noticeably thinner. The cell count and thickness in the electrodeless lamp and LED groups differed from those in the normal control group, with the LED group showing fewer cell numbers than the normal control group (p < 0.01). Both LED and electrodeless lamp exposure led to retinal cell death, elevated protein levels of HSP70, Bcl-2-associated X protein (Bax) and Cleaved caspase-3, while diminishing the level of B-cell lymphoma-2 (Bcl-2) (p < 0.01). Conclusion: Exposure to electrodeless lamp and LED lamp results in damage to the retinas of guinea pigs.