650 nm red light enhances aldehyde dehydrogenase 3A1 expression in retina pigment epithelial cells in vitro and in vivo

Purpose: Low-dose 650 nm red light has been found to slow myopia progression, although the underlying mechanisms remain unclear. This study aimed to investigate its antioxidative effects and molecular pathways. Methods: An oxidative stress model was established in ARPE-19 cells by treatment with hydrogen peroxide (H2O2) at concentrations of 0, 0.5, and 0.75 mM. The cells were then irradiated with red light for 9 minutes, twice daily for 2 days, with an equivalent-power white light group serving as a control. Following irradiation, oxidative stress was quantified using a DCFH-DA assay, and DNA damage was assessed by γ-H2AX immunofluorescence. For the in vivo study, mice received ocular irradiation with red light (9 minutes/session, twice daily for 5 days) using a white light-exposed group as a control. Changes in axial length were measured post irradiation using anterior segment optical coherence tomography. Subsequently, retinal pigment epithelial (RPE) cells were isolated from the mice for RNA sequencing to analyze differential mRNA expression. Quantitative real-time PCR (qPCR) and Western blotting were employed to validate the expression of specific genes associated with ocular diseases. Results: At a concentration of 0.75 mM hydrogen peroxide, red light irradiation significantly reduces oxidative stress levels compared to the control group. RNA sequencing data revealed that there were 274 genes upregulated and 225 genes downregulated in RPE cells from mouse eyes illuminated with the 650 nm red light. The gene encoding aldehyde dehydrogenase 3A1 (ALDH3A1), which is significantly upregulated after red light irradiation, plays an important role in protecting ocular structures from oxidative damage. qPCR and Western blot analyses confirmed that ALDH3A1 was heightened in RPE cells from mouse eyes in vivo and in cultured human RPE cells in vitro illuminated by the 650 nm red light. Conclusions: ALDH3A1 may play a part in myopia improvement upon 650 nm red light illumination.