Pre-treatment but not co-treatment with vitexin alleviates hyperthermia induced oxidative stress and inflammation in buffalo mammary epithelial cells

Abstract

This study investigated if in vitro supplementation of vitexin could mitigate the adverse effects of hyperthermia on buffalo mammary epithelial cells (BuMECs). Immortalized BuMECs were divided into seven groups (n = 3): (1) a negative control group at 37 °C; (2) BuMECs exposed to heat stress as a positive control at 42 °C for 1 h; (3−7) heat stressed BuMECs pre-treated or co-treated with different concentrations of vitexin (5 μM, 10 μM, 20 μM, 50 μM, and 100 μM), respectively. Hyperthermia was induced by exposing the cells to 42 ºC for 1 h. For the pre-treatment experiment, BuMECs were treated with vitexin for 2 h before hyperthermia exposure. For co-treatment, vitexin was added simultaneously with hyperthermia for 1 h. Subsequently, the cells were allowed to recover for 12 h at 37 °C. Results showed that pre-treatment with vitexin was more effective than co-treatment in protecting BuMECs from hyperthermia in a dose-dependent manner, with higher concentrations (50 μM and 100 μM) being the most effective. Pre-treatment with vitexin maintained cellular viability and prevented inflammation by inducing the expression of the anti-apoptotic gene (BCL-2) and reducing the expression of the pro-apoptotic gene (Bax) and pro-inflammatory mediators (IL-1β, IL-6) in heat-stressed BuMECs. Pre-treatment with vitexin reduced oxidative stress and induced thermotolerance by increasing the expression of antioxidants mediators such as SOD, GPx and CAT at mRNA and protein levels, and modulating the expression of heat shock proteins. The findings suggest that vitexin has the potential as a therapeutic agent to protect the mammary gland from the negative impact of hyperthermia in dairy cows.