title: Characterization of TLR2, NOD2, and related cytokines in mammary glands infected by Staphylococcus aureus in a rat model.
abstract: BACKGROUND
  Staphylococcus aureus causes subclinical mastitis as well as persistent and chronic infections in cattle. Bovine mastitis induced by S. aureus is often refractory to antibiotic treatment. Local innate immune defenses play an important role in eliminating the invading bacteria. TLR2 and NOD2 are important pathogen recognition receptors, but their functions have not been investigated in the context of early stages of mastitis. The present study examined TLR2, NOD2, and related cytokines in mammary glands infection induced by S. aureus at early stages in a rat mastitis model.
  
  
  RESULTS
  All inoculated mammary glands developed mastitis. Acute changes were induced in mammary tissues infected with S. aureus at early stages and then chronic infections persisted until the end of the experiment. TLR2 and NOD2 mRNA expression increased significantly after inoculation with S. aureus. The expression levels of cytokine mRNAs, including TNF-α, IL-1β, IL-6, IL-10, and CXCL1, also increased. TGF-β1 expression was suppressed at early phase and IFN-γ mRNA expression increased significantly at a later stage.
  
  
  CONCLUSIONS
  Mammary innate immune responses were activated after S. aureus inoculation. TLR2, NOD2, and inflammatory cytokines (TNF-α, IL-1β, IL-6, CXCL1, IL-10, TGF-β1, and IFN-γ) are involved in the response to mastitis induced by S. aureus.
authors.affiliation: College of Veterinary Medicine, Yangzhou University, Yangzhou, Jiangsu, 225009, China. sdaulellow@163.com.|Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, Jiangsu, 225009, China. sdaulellow@163.com.
authors.forename: Heng
authors.initials: H
authors.lastname: Wang
authors.affiliation: College of Veterinary Medicine, Yangzhou University, Yangzhou, Jiangsu, 225009, China. 742040984@qq.com.|Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, Jiangsu, 225009, China. 742040984@qq.com.
authors.forename: Guangtao
authors.initials: G
authors.lastname: Yu
authors.affiliation: College of Veterinary Medicine, Yangzhou University, Yangzhou, Jiangsu, 225009, China. 1360196131@qq.com.|Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, Jiangsu, 225009, China. 1360196131@qq.com.
authors.forename: Hui
authors.initials: H
authors.lastname: Yu
authors.affiliation: College of Veterinary Medicine, Yangzhou University, Yangzhou, Jiangsu, 225009, China. 501621657@qq.com.|Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, Jiangsu, 225009, China. 501621657@qq.com.
authors.forename: Mingjie
authors.initials: M
authors.lastname: Gu
authors.affiliation: College of Veterinary Medicine, Yangzhou University, Yangzhou, Jiangsu, 225009, China. qingse2005@163.com.|Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, Jiangsu, 225009, China. qingse2005@163.com.
authors.forename: Jun
authors.initials: J
authors.lastname: Zhang
authors.affiliation: College of Veterinary Medicine, Yangzhou University, Yangzhou, Jiangsu, 225009, China. mengxia_1@126.com.|Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, Jiangsu, 225009, China. mengxia_1@126.com.
authors.forename: Xia
authors.initials: X
authors.lastname: Meng
authors.affiliation: College of Veterinary Medicine, Yangzhou University, Yangzhou, Jiangsu, 225009, China. liuzongping@yzu.edu.cn.|Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, Jiangsu, 225009, China. liuzongping@yzu.edu.cn.
authors.forename: Zongping
authors.initials: Z
authors.lastname: Liu
authors.affiliation: College of Animal Science and Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei, 430070, China. sdqiu2001@163.com.
authors.forename: Changwei
authors.initials: C
authors.lastname: Qiu
authors.affiliation: College of Veterinary Medicine, Yangzhou University, Yangzhou, Jiangsu, 225009, China. yzjjli@163.com.|Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, Jiangsu, 225009, China. yzjjli@163.com.
authors.forename: Jianji
authors.initials: J
authors.lastname: Li
mesh_terms: D000818:Animals; D002417:Cattle; D016207:Cytokines / Q000235:genetics / Q000378:metabolism; D004195:Disease Models, Animal; D005260:Female; D008321:Mammary Glands, Animal / Q000276:immunology; D008414:Mastitis, Bovine / Q000276:immunology* / Q000382:microbiology; D053473:Nod2 Signaling Adaptor Protein / Q000235:genetics* / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D060888:Real-Time Polymerase Chain Reaction / Q000662:veterinary; D013203:Staphylococcal Infections / Q000382:microbiology / Q000503:physiopathology / Q000662:veterinary*; D013211:Staphylococcus aureus / Q000502:physiology*; D051195:Toll-Like Receptor 2 / Q000235:genetics* / Q000378:metabolism
chemical_list: D016207:Cytokines; C512493:NOD2 protein, rat; D053473:Nod2 Signaling Adaptor Protein; C495343:Tlr2 protein, rat; D051195:Toll-Like Receptor 2