MPO and mastitis: ATF can reduce the pathological damage of LPS-induced mastitis in mice, decrease MPO activity and inflammatory factor secretion in mammary tissue and serum, inhibit mRNA expression of key genes in the CD14/TLR4/NF-κB/MAPK signalling pathway and promote mRNA expression of tight junction proteins in the blood-milk barrier, effectively improving the inflammatory response of LPS-induced mammary tissue in mice.