Protective effects of microalgal macular pigment on diabetic retinopathy upon blue light irradiation induced oxidative stress, inflammation, and MAPK pathways

Abstract

Microalgae and their rich nutrient content are increasingly recognized as a sustainable food source. Microalgal macular pigment (MP), composed of zeaxanthin and lutein, is densely concentrated in the retinal macula of eyes and is frequently utilized in eye health maintenance. However, as a sustainable food ingredient, the food safety and functionality of MP need further investigated. There is a lack of scientific studies exploring the protective mechanisms of microalgal MP on diabetic vascular lesions. This study aimed to investigate the effects of MP isolated from Chlorella sp. AT1 in reducing diabetic retinopathy damage in both in vitro and in vivo systems. The microalgal extract is rich MP, with zeaxanthin and lutein in a ratio 1:5. Blue light (BL) irradiation and hyperglycemia increased reactive oxygen species production, and elevated inflammatory factors, including COX-2, NF-κB, and the proteins associated with mitogen activated protein kinase (MAPK) signaling pathway in adult retinal pigment epithelial cells (ARPE-19) and human umbilical vein endothelial cells (HUVEC). However, MP administration significantly mitigated the adverse effects caused by BL exposure and hyperglycemia. In vivo, MP supplementation significantly reduced inflammatory cytokines (TNF-α and IL-6), inflammation-related proteins (iNOS, COX-2, and NF-κB), MAPK pathway proteins, and adhesion factors (ICAM and VCAM) induced by BL irradiation in retinal tissues of diabetic mice. Microalge MP improves inflammatory responses and oxidative stress in diabetic retinopathy under BL irradiation. These findings demonstrate that MP from Chlorella sp. AT1 is a promising sustainable food pigment with protective properties against diabetic vascular disease.