Study of the antioxidant capacity of astaxanthin in cells against radiation-induced strong oxidative stress

Astaxanthin, an oxygen-containing carotenoid derived from Haematococcus pluvialis, has excellent antioxidant properties and great potential in antioxidant, immunomodulation, anti-cancer, skin protection and aquaculture. However, the protective effect of astaxanthin on cells under the strong oxidative stress caused by external factors such as ionizing radiation has not been investigated. For this purpose, we employed γ-ray, one type of strong energy-penetrating radiations, to irradiate the normal cells, namely, BHK-21 and CHO-K1 cells, and studied the antioxidant capacity, or, the protective effect of astaxanthin in the cells. Our results showed that astaxanthin could significantly enhance the cell viability of the cells under radiation conditions by decreasing reactive oxygen species (ROS) in the cells and reducing the radiation-caused DNA damage. Furthermore, we found that the antioxidant proteins HO-1 and p-Nrf2 were upregulated due to astaxanthin treatment, which activated the Nrf2 signaling pathway and alleviated the oxidative stress imposed by the ionizing radiation. This study therefore not only provides the evidence of the extraordinary antioxidant property of astaxanthin, but also may extend its application in radiation protection areas.