Quercetin is associated with photoreceptor protection in retinal degeneration

Retinal degeneration (RD) is a group of retinopathies characterized by progressive photoreceptor death and chronic neuroinflammation. Quercetin (QUE) is a natural flavonol with potent anti-inflammatory and free-radical scavenging properties. However, its protective effects against RD remain poorly characterized. This study aims to investigate the therapeutic potential of QUE on RD.In vitro and in vivo models of sodium iodate (NaIO 3 )-induced oxidative damage were used to evaluate the effects of QUE in RD. NaIO 3 was used to induce oxidative damage in 661W cells. QUE was added to the cell cultures, and cell viability and oxidative markers were assessed. In vivo, QUE was delivered into the vitreous cavity of NaIO 3 -induced RD mice, followed by morphological analysis, visual function evaluation, behavioral testing, and Western blot detection.QUE protected 661W cells from NaIO 3 -induced oxidative damage by reducing intracellular reactive oxygen species, restoring mitochondrial membrane potential, and alleviating mitochondrial membrane pore disruption. In vivo, intravitreal QUE injection preserved retinal structure, reduced lesion area, elevated electroretinogram P-wave amplitude, and improved behavioral performance. QUE administration was accompanied by alleviated oxidative stress, inhibited glial activation, reduced pro-inflammatory cytokines, and elevated p-PI3K and p-AKT expression in RD. Neuroinflammation and oxidative stress are involved in RD pathology. These findings provide preliminary evidence that QUE exerts protective effects on photoreceptors in NaIO₃-induced RD. No causal relationship between PI3K/AKT activation and the retinal protection of QUE was established in this study.