The preventive effects of Lactobacillus casei 03 on Escherichia coli-induced mastitis in vitro and in vivo.

ABSTRACT

BACKGROUND: Lactobacillus casei possesses many kinds of bioactivities, such as anti-inflammation and anti-oxidant, and has been applied to treating multiple inflammatory diseases. However, its role in mastitis prevention has remained ambiguous. METHODS: This study aimed to examine the mechanisms underlying the preventive effects of L. casei 03 against E. coli- mastitis utilizing bovine mammary epithelial cells (BMECs) and a mouse model. RESULTS: In vitro assays revealed pretreatment with L. casei 03 reduced the apoptotic ratio and the mRNA expression levels of IL1ß, IL6 and TNFα and suppressed phosphorylation of p65, IκBα, p38, JNK and ERK in the NF-κB signaling pathway and MAPK signaling pathway. Furthermore, in vivo tests indicated that intramammary infusion of L. casei 03 relieved pathological changes, reduced the secretion of IL1ß, IL6 and TNFα and MPO activity in the mouse mastitis model. CONCLUSIONS: These data suggest that L. casei 03 exerts protective effects against E. coli-induced mastitis in vitro and in vivo and may hold promise as a novel agent for the prevention and treatment of mastitis.