Abstract
Age-related macular degeneration (AMD) is a significant visual impairment in older people, and there is no treatment for dry AMD. Spirulina maxima (S. maxima), a cyanobacterium, has inhibitory effects against oxidative stress. However, the protective effects of S. maxima and its underlying mechanisms on blue light (BL)-caused macular degeneration are unknown. We aimed to investigate the protective effects of S. maxima on blue light-caused retinal damage and demonstrate its underlying mechanisms in human retinal pigment epithelial (ARPE-19) cells and Balb/c retinas. Additionally, the active component of S. maxima was examined in the RPE cells. In vitro, S. maxima decreased BL-induced RPE cell death by inhibiting reactive oxygen species (ROS) production. S. maxima inhibited BL-induced inflammation via regulating the NF-κB pathway, inflammatory-related gene expression, and the apoptosis pathway in RPE cells. In vivo, administration of S. maxima inhibited BL-induced retinal degeneration by restoring the thicknesses of whole retina, ONL (outer nuclear layer), INL (inner nuclear layer), and PL (photoreceptor layer) by BL exposure. Phycocyanin exerted protective effects in the pre-and post-treatment system. Therefore, S. maxima could be a potential nutraceutical approach to intercept the patho-physiological processes leading to dry AMD and advancement to wet AMD. Moreover, phycocyanin was a major active compound of S. maxima. These findings need to be investigated in human studies, particularly through a clinical trial.
Highlights
The usage of electronic devices, including television, computers, and smartphones, has risen, resulting in increased exposure to blue light (BL) [1,2]
S. maxima Inhibited Cell Death Caused by A2E Treatment and BL Exposure
The retinal pigment epithelial (RPE) cells were treated with various concentrations of S. maxima (0, 50, 100, 200, 400, and 800 μg/mL), and S. maxima did not show cytotoxicity
Summary
The usage of electronic devices, including television, computers, and smartphones, has risen, resulting in increased exposure to blue light (BL) [1,2]. As blue light has relatively shorter wavelengths and higher energy in the visible light spectrum, it is mainly known that BL damages ocular tissues, including retinas and lens, causing several ocular diseases such as macular degeneration, cataracts, and xerophthalmia [3]. Age-related macular degeneration (AMD) is a degenerative eye disease in the elderly characterized by deposited drusen, abnormal function of retinal pigment epithelial (RPE) cells, and abnormal neovascularization causing impaired vision. RPE cells are crucial for assisting photoreceptor cells in performing the normal visual function. All-trans-retinal is formed by the visual cycle and reacts with phosphatidylethanolamine to synthesize N-retinylidene-N-retinylethanolamine (A2E) [2]. The treatment of injecting anti-vascular endothelial growth factor (VEGF) can be performed to delay vision impairments caused by neovascularization [9]
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