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

Authors: LIN, MENG-WEI - Washington State University; LIN, CHENG-HAN - National Yang-Ming University; CHIU, WEI-HONG - National Yang-Ming University; CHANG, HUI-FANG - Hsinchu Mackay Memorial Hospital; CHEANG, WAI-MAN - Taichung Tzu Chi Hospital; CHANG, CHIEN-CHUN - Taichung Tzu Chi Hospital; Wu, Vivian; LIN, CHIH-SHENG - National Yang-Ming University; KUO, CHIU-MEI - Chung Yuan Christian University

Submitted to: Food Research International
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/29/2025
Publication Date: 7/3/2025
Citation: Lin, M., Lin, C., Chiu, W., Chang, H., Cheang, W., Chang, C., Wu, V.C., Lin, C., Kuo, C. 2025. Protective effects of microalgal macular pigment on diabetic retinopathy upon blue light irradiation induced oxidative stress, inflammation, and MAPK pathways. Food Research International. 219. Article 116978. https://doi.org/10.1016/j.foodres.2025.116978.
DOI: https://doi.org/10.1016/j.foodres.2025.116978

Interpretive Summary: Microalgae are tiny plants that can do many things. They help the environment by taking in carbon, and they can make useful products. Some microalgae make macular pigment (MP). MP is composed of zeaxanthin and lutein. These are found in a part of the eye called the macula. Scientists haven't done much research to see if MP can protect the eyes from the damage caused by diabetes. So, in this study, we found that Chlorella sp. has a lot of MP, with a 1:5 ratio of zeaxanthin to lutein, which suggests a beneficial effect on eye health. We gave this MP to mice with diabetes and exposed their eyes to blue light, which can also damage the eyes. We discovered that the MP helped protect the diabetic mice's eyes. It reduced the damage caused by both high blood sugar and blue light. The MP also lowered harmful things called oxidative stress and inflammation in the eye tissue. This study shows that MP from microalgae can help reduce the damage by fighting inflammation and oxidative stress.

Technical Abstract: Microalgae are multi-functional options in modern agriculture for carbon neutrality and bioproduct production. Microalgal macular pigment (MP), composed of zeaxanthin and lutein, is densely concentrated in the retinal macula of the eyes and is frequently utilized in eye health maintenance. However, there is a dearth of scientific investigations delving into the protective mechanisms of microalgal MP. Therefore, the present study aimed to investigate the effects of MP isolated from a microalga Chlorella sp. AT1-6 on diminishing diabetic retinopathy damage in both in vitro and in vivo systems. The extract of Chlorella sp. contains rich MP with zeaxanthin and lutein in a ratio of 1:5. Blue light (BL) irradiation and hyperglycemia increased reactive oxygen species production, the inflammatory factors levels, including COX-2, NF-'B, and the proteins associated with MAPK signaling pathway in retinal pigment epithelial cells (ARPE-19) and human umbilical vein endothelial cells (HUVEC). However, MP administration significantly moderated the adverse effects caused by BL exposure and hyperglycemia. The in vivo results indicate that MP supplementation significantly reduced the levels of inflammatory cytokines (TNF-a and IL-6), inflammation proteins (iNOS, COX-2, and NF-'B), MAPK pathway proteins, and adhesion factors (ICAM and VCAM) induced by BL irradiation in retinal tissues of diabetic ApoE-/- mice. The MP extracted from the microalga Chlorella sp. has the benefits of improving inflammatory responses and oxidative stress in diabetic retinopathy upon BL irradiation.