Abstract
BackgroundTea tree oil (TTO) plays an important role in antibacterial activity and alleviating the inflammatory responses. Bovine mammary epithelium and polymorphonuclear leukocytes (PMNL) can actively respond to bovine mastitis infection. However, regulatory effects of TTO extracts on the innate immune response of bovine mammary epithelial cells (BMECs) and PMNL remain not reported. Therefore, aim of the study was to evaluate the effects of TTO extracts on the mRNA levels of the genes involved in the innate immune response of BMECs and PMNL.ResultsOur results demonstrated that addition of 0.025% and 0.05% TTO increased the proliferation of BMECs, and significantly enhanced (P < 0.05) the viability of BMECs exposed to Staphylococcus aureus (S. aureus). An inhibitory effect was observed against the growth of S. aureus by TTO incubation. The 0.05% TTO reduced S. aureus biofilm formation, association and invasion of S. aureus to BMECs, and changed the morphological and structural features of S. aureus. The proinflammatory cytokines IL-1β, IL-6, and TNF-α were decreased (P < 0.001) by the incubation of TTO. Interestingly, the expression of IL-8 known for PMNL chemotactic function was elevated (P < 0.05) by 0.05% TTO treatment. Consistently, 0.05% TTO increased the migration of PMNL in S. aureus-exposed BMECs when compared with S. aureus treatment alone (P < 0.05). In addition, PMNL incubated with 0.05% TTO decreased the levels of NFKB inhibitor alpha (NFKBIA) and TNF-α.ConclusionsOur results indicate that use of TTO can relieve the BMECs pro-inflammatory response caused by S. aureus and promote the migration of PMNL to mount the innate immune responses, and it may be novel strategy for the treatment of bovine mastitis caused by S. aureus.
Highlights
Bovine mastitis, an inflammation of mammary gland, is a serious infectious disease involved in the infection with a pathogen, such as Staphylococcus aureus (S. aureus), Escherichia coli, and Streptococcus [1], and results in decreased milk quality [2] and economic losses [3]
The present study showed that association of S. aureus to bovine mammary epithelial cells (BMECs) and invasion of S. aureus into BMECs were significantly reduced by treatment with 0.05% and 0.1% Tea tree oil (TTO), compared with control group (Fig. 3c and d)
The present study indicates that 0.025% and 0.05% concentration of TTO increased the proliferation of BMECs, and enhanced the viability of BMECs exposed to S. aureus
Summary
An inflammation of mammary gland, is a serious infectious disease involved in the infection with a pathogen, such as Staphylococcus aureus (S. aureus), Escherichia coli, and Streptococcus [1], and results in decreased milk quality [2] and economic losses [3]. Bovine mastitis is divided into clinical and subclinical mastitis. Clinical mastitis is readily observed and detected by abnormal milk secretions, whereas subclinical mastitis is asymptomatic and difficult to be observed and is diagnosed by the reservoir of pathogen infection in milk [4]. Bovine mammary epithelium and polymorphonuclear leukocytes (PMNL) can actively respond to bovine mastitis infection. Regulatory effects of TTO extracts on the innate immune response of bovine mammary epithelial cells (BMECs) and PMNL remain not reported.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
