AUTHOR=Feng Yanzhong , An Zhimin , Chen Heshu , He Xinmiao , Wang Wentao , Li Xiang , Zhang Haifeng , Li Fenglan , Liu Di 

TITLE=Ulva prolifera Extract Alleviates Intestinal Oxidative Stress via Nrf2 Signaling in Weaned Piglets Challenged With Hydrogen Peroxide

JOURNAL=Frontiers in Immunology

VOLUME=11

YEAR=2020

URL=https://www.frontiersin.org/journals/immunology/articles/10.3389/fimmu.2020.599735

DOI=10.3389/fimmu.2020.599735

ISSN=1664-3224

ABSTRACT=<sec><title>Background</title><p><italic>Ulva prolifera</italic> extract contains a variety of functional active substances. Whether these substances had any beneficial effects on the small intestine of weaned piglets under oxidative stress remained unknown.</p></sec><sec><title>Method</title><p>We explored the effects of <italic>U. prolifera</italic> extract on oxidative stress and related mechanisms in weaned piglets and intestinal porcine epithelial cells (IPEC-J2) challenged with hydrogen peroxide.</p></sec><sec><title>Results</title><p><italic>U. prolifera</italic> extract was found to mainly consist of polyphenols and unsaturated fatty acids<italic>. U. prolifera</italic> extract increased total antioxidant capacity and superoxide dismutase (SOD) activity, while it decreased malondialdehyde content, in the serum of weaned piglets challenged with hydrogen peroxide. Moreover, <italic>U. prolifera</italic> extract increased mRNA expression of <italic>SOD</italic> and <italic>catalase</italic>, as well as the intestinal expression of nuclear NF-E2-related factor 2 (Nrf2), both <italic>in vitro</italic> and <italic>in vivo</italic>. Furthermore, <italic>U. prolifera</italic> extract decreased reactive oxygen species and improved mitochondrial respiration in IPEC-J2 cells treated with hydrogen peroxide. However, AMPK inhibition did not affect nuclear Nrf2 expression and only partially affected the effects of <italic>U. prolifera</italic> extract on oxidative stress.</p></sec><sec><title>Conclusion</title><p>We suggest that <italic>U. prolifera</italic> extract alleviates oxidative stress <italic>via</italic> Nrf2 signaling, but independent of AMPK pathway in weaned piglets challenged with hydrogen peroxide. These results shed new insight into the potential applications of <italic>U. prolifera</italic> extract as a therapeutic agent for the prevention and treatment of oxidative stress-induced intestinal diseases.</p></sec>