Topical Area: Carotenoids and Retinoids (CARIG)
Objectives : Macrophages play crucial roles in the development of alcohol-induced inflammation. We previously demonstrated the inhibitory effects of astaxanthin (ASTX), a xanthophyll carotenoid, on the expression of pro-inflammatory and antioxidant genes as well as cellular accumulation of reactive oxygen species (ROS) in macrophages stimulated with lipopolysaccharides. The objective of this study was to determine whether ASTX can prevent alcohol-induced inflammation and oxidative stress in macrophages with the elucidation of the underlying mechanisms.
Methods : RAW 264.7 macrophages, a murine macrophage cell line, and mouse bone marrow-derived macrophages (BMDM) were treated with 80 mM ethanol in the absence or presence of 25 mM of ASTX for 72 h with daily media change. The expression levels of pro-inflammatory and antioxidant genes and proteins were measured by quantitative real-time PCR and Western blot, respectively. Cellular ROS accumulation was also determined in both macrophage cell types.
Results : ASTX significantly decreased ethanol-induced mRNA expression of interleukin (IL)-6, IL-1β, and tumor necrosis factor α (TNFα) as well as TNFα secretion in RAW 264.7 macrophages. Elevated levels of cellular ROS levels by ethanol were also attenuated by ASTX with a concomitant decrease in the expression of NADPH oxidase 2, a ROS-producing enzyme, in RAW 264.7 macrophages. The similar inhibitory effects of ASTX on inflammatory gene expression and cellular ROS accumulation were observed with BMDM. Furthermore, ethanol significantly decreased in sirtuin1 (SIRT1) mRNA and protein levels, which were markedly attenuated by ASTX in RAW 264.7 macrophages.
ASTX inhibited the expression and production of pro-inflammatory mediators and ROS accumulation in both RAW 264.7 macrophages and BMDM when the cells were exposed to ethanol. The anti-inflammatory effect of ASTX in ethanol-treated macrophages may be mediated, at least in part, by the activation of the SIRT1 pathway. Thus, ASTX may be used for the prevention of inflammatory and oxidative conditions triggered by excessive alcohol consumption.
Funding Sources : This study was supported by USDA Multistate Hatch.