Paeonol attenuates LPS-induced inflammatory injury in mastitis by regulating the MAPK and Nrf2 signaling pathways.

Mastitis is an inflammatory udder disease that causes important economic losses in the animal breeding and dairy product industries. While antibiotics have contributed to disease control, their use presents risks due to drug residues in livestock products that can potentially threaten human health. Paeonol, an active ingredient extracted from the dried root bark of paeonia suffruticosa, exhibits various pharmacological effects, including anti-inflammatory and antibacterial properties, but its role in mastitis remains unclear. In this study, we first evaluated the effects of paeonol on LPS-induced mastitis in mice and further explored the potential anti-inflammatory mechanism of paeonol on bovine mammary epithelial cells (BMECs). The results showed that paeonol alleviated LPS-induced mouse mastitis by inhibiting the infiltration of inflammatory cells and the release of inflammatory factors. Cellular assays further demonstrated that paeonol reduced apoptosis and inhibited inflammation and oxidative stress injury by mechanisms involving activation of Nrf2 signaling and inhibition of MAPK signaling in BMECs. Collectively, our results suggest that paeonol holds promise as a therapeutic agent for alleviating LPS-induced mastitis injury while providing novel insights into potential drug targets for mastitis treatment.