Anti-inflammatory effects of apigenin on LPS-induced mastitis in lactating SD rats through inhibiting TLR4/NF-κB signaling pathway

Mastitis is an important disease of the mammary gland in all kinds of lactating mammals, endangering the development of animal husbandry and human health. Apigenin is one chemical constituent of Taraxacum and Philippine Violet Herb which are effective Chinese herbs for the treatment of mastitis. It is reported that apigenin possesses anti-inflammatory activity and other pharmacological effects. However, the attenuation of apigenin on mastitis has not yet been reported. The present study investigated the protection of apigenin against lipopolysaccharide (LPS)-induced mastitis in SD rats both in vivo and in vitro. The results suggested that apigenin relieved the lesions of mammary tissues induced by LPS, decreased mRNA and protein levels of pro-inflammatory cytokines:tumor necrosis factor-alpha (TNF-α), interleukin-1β (IL-1β), and interleukin-6 (IL-6). Simultaneously, apigenin reduced the increasing content of myeloperoxidase (MPO) and Toll-like receptor 4 (TLR4), and phosphorylation of nuclear factor kappa B (NF-κB) induced by LPS. The results showed that apigenin was able to attenuate the LPS-induced mastitis in rats by inhibiting the TLR4/NF-κB signaling pathway in vivo and in vitro, which provides scientific references for further research.