Proanthocyanidins Protect against β-Hydroxybutyrate-Induced Oxidative Damage in Bovine Endometrial Cells

Abstract

Metabolic diseases, such as ketosis, are closely associated with decreased reproductive performance (such as delayed estrus and decreased pregnancy rate) in dairy cows. The change of <i>β-hydroxybutyrate</i> (<i>BHBA</i>) concentration in dairy cattle is an important mechanism leading to ketosis, and its blood concentration in ketotic cows is always significantly higher than in nonketotic cows. Many studies indicated that <i>BHBA</i> can induce oxidative damage in liver and other organs. <i>Proanthocyanidins</i> (<i>PCs</i>) have gained substantial attention in the last decade as strong antioxidative substances. This study aimed to demonstrate a protective effect of <i>PCs</i> against <i>BHBA</i>-induced oxidative stress damage in bovine endometrial (BEND) cells by activating the <i>nuclear erythroid2-related factor2</i> (<i>Nrf2</i>) signaling pathway. Our research show that <i>PCs</i> could significantly increase activities of <i>catalase</i> (<i>CAT</i>) and <i>glutathione peroxidase</i> (<i>GSH-PX</i>), <i>glutathione</i> (<i>GSH</i>) content, and <i>antioxidant capacity</i> (<i>T-AOC</i>), while significantly decreasing <i>malondialdehyde</i> (<i>MDA</i>) content in BEND cells. Both mRNA and protein expression levels of <i>Nrf2</i> were significantly increased in BEND cells, and <i>glutamate⁻cysteine ligase catalytic subunit</i> (<i>GCLC</i>), heme <i>oxygenase 1</i> (<i>HO-1</i>), <i>manganese superoxide dismutase</i> (<i>Mn-SOD</i>), and <i>NAD(P)H</i> <i>quinone dehydrogenase 1</i> (<i>NQO-1</i>) were also significantly increased. These results indicate that <i>PCs</i> can antagonize <i>BHBA</i>-induced oxidative damage by activating the <i>Nrf2</i> signaling pathway to exert an antioxidant effect.