Lycium barbarum glycopeptide and luteolin synergistically protect mouse photoreceptors against N-nitroso-N-methylurea-induced degeneration

Photoreceptor degeneration is a major cause of vision impairment in retinal diseases, for which no effective treatment currently exists. Previous research by our team demonstrated that Lycium barbarum glycopeptide and luteolin can independently promote photoreceptor survival and function in degenerated mouse retinas, although with limited efficacy. This study evaluated whether a combination of Lycium barbarum glycopeptide and luteolin provides enhanced therapeutic benefits compared with either compound alone. Wild-type mice received a daily oral gavage of Lycium barbarum glycopeptide and luteolin for 7 days prior to intraperitoneal injection of N-nitroso-N-methylurea to induce photoreceptor damage. The treatment continued for an additional week after injury. Retinal structure and function were subsequently assessed using electroretinogram recordings, visual behavior testing, and immunostaining. Western blot analysis was conducted to investigate the underlying protective mechanisms. The results showed that the Lycium barbarum glycopeptide-luteolin mixture significantly increased photoreceptor survival, improved retinal light response, and enhanced visual behavior. Importantly, the combination outperformed either compound alone in protective efficacy. Mechanistic analysis indicated that the mixture suppressed retinal inflammation and modulated the extracellular signal-regulated kinase and Bcl-2-associated X protein/B-cell lymphoma 2 signaling pathways. These findings suggest that the combination of Lycium barbarum glycopeptide and luteolin represents a promising therapeutic strategy for photoreceptor degeneration.