Dietary Supplementation with Beta-Cryptoxanthin (BCX) Protects Against Light-Induced Retinal Damage

Abstract

Abstract Objectives The retinal pigment epithelium (RPE) regulates the transport of nutrients and waste products to and from the retina and protects against light and oxidative stress. Structural or physiological dysfunction of RPE leads to retinal conditions such as age-related eye disease (ARED). It is well-established that artificial and natural light is an important factor in the progression of ARED as it can induce oxidative damage and photochemical lesions. Recently, the use of LED in general lighting has raised concerns regarding the effects of this light source on the RPE. The goal was to investigate whether beta-cryptoxanthin, an efficient pro-vitamin A carotenoid can exert protective effects against LED-induced RPE cell damage. Methods Rats were fed with BCX for 4 weeks at a dose of 2 and 4 mg/kg body weight followed by retinal damage by exposing the eye to bright LED light for 48 hrs. Commercially available white LED sources, which are widely used in rat housing studies was used to induce retinal damage. Animals were sacrificed at the end of the study and retinal tissue and blood samples were collected and evaluated for retinal damage and markers of oxidative stress. Results BCX supplementation significantly reduced retinal damage as demonstrated by histopathology measurements including total retinal thickness, outer nuclear layer thickness, and swelling. Similarly, markers of oxidative stress including serum and retinal tissue levels of malondialdehyde, superoxide dismutase, glutathione peroxidase, and catalase were beneficially modulated by BCX supplementation. In parallel, BCX supplementation reduced inflammatory markers (IL-1β, IL-6, NF-κB), angiogenic factor VEGF, apoptotic proteins (Caspase-3, GAP43, GFAP, NCAM, HO-1) and mitochondrial stress markers (ATF4, ATF6, Grp78, Grp97) in retinal tissue. Conclusions Our study supports that oral supplementation of BCX dose-dependently exerts a protective effect against retinal damage induced by high-intensity light in a rat model by reducing oxidative stress, inflammation, angigogenesis and protection against mitochondrial DNA damage. BCX dietary intakes and supplementation throughout all stages of life can help protect against ARED that may start early in life. Funding Sources OmniActive Health Technologies.