title: Nicotine inhibits LPS-induced cytokine production and leukocyte infiltration in rat placenta.
abstract: BACKGROUND
  Previous work conducted by our group has shown that nicotine reduces lipopolysaccharide (LPS)-induced systemic inflammatory responses and protects fetuses in pregnant Sprague-Dawley (SD) rats. In the present study, we aim to evaluate the influence of nicotine on rat placenta, including cytokine release, leukocyte infiltration, and α7 nicotinic acetylcholine receptor (α7-nAChR) expression.
  
  
  METHODS
  Placental tissues of SD rats on gestation day 14 (GD14) were obtained and cultured in the presence or absence of LPS and/or nicotine. Culture media after 24 h were analyzed for cytokines release using Luminex. Other pregnant SD rats were first pretreated with nicotine on GD14 and GD15, followed by LPS injection on GD16. Placentas were collected on GD18 for H&E staining to evaluate leukocyte density and for real-time PCR and western blotting to identify the α7-nAChR expression in different groups.
  
  
  RESULTS
  Nicotine suppresses LPS-stimulated placental proinflammatory cytokines (IL-1, IL-2, IL-6, TNF-α, IFN-γ) production except IL-17 in vitro, and reduces leucocytes infiltration in the placental chorionic plate caused by LPS in vivo. Moreover, LPS increases the α7-nAChR protein expression in placentas while pretreatment of nicotine inhibits it.
  
  
  CONCLUSIONS
  These data show that nicotine suppresses LPS-induced placental inflammation by inhibition of cytokine release and infiltration of leukocytes into the placenta, and regulates the increased expression of α7-nAChR in placenta after LPS treatment. Nicotine and other nicotinic agonists may be an alternative therapeutic strategy for placental inflammation.
authors.affiliation: Department of Obstetrics and Gynecology, Preterm Birth Prevention and Treatment Research Unit, Guangzhou Women & Children's Medical Center, Guangzhou Medical University, Guangzhou, China.
authors.forename: Junjie
authors.initials: J
authors.lastname: Bao
authors.affiliation: Department of Obstetrics and Gynecology, Preterm Birth Prevention and Treatment Research Unit, Guangzhou Women & Children's Medical Center, Guangzhou Medical University, Guangzhou, China.
authors.forename: Yuanyuan
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Department of Obstetrics and Gynecology, Preterm Birth Prevention and Treatment Research Unit, Guangzhou Women & Children's Medical Center, Guangzhou Medical University, Guangzhou, China.
authors.forename: Jinying
authors.initials: J
authors.lastname: Yang
authors.affiliation: Department of Pathology, Guangzhou Women & Children's Medical Center, Guangzhou Medical University, Guangzhou, China.
authors.forename: Qiu
authors.initials: Q
authors.lastname: Gao
authors.affiliation: Department of Obstetrics and Gynecology, Preterm Birth Prevention and Treatment Research Unit, Guangzhou Women & Children's Medical Center, Guangzhou Medical University, Guangzhou, China.
authors.forename: Shao-Qing
authors.initials: SQ
authors.lastname: Shi
authors.affiliation: Department of Obstetrics and Gynecology, Preterm Birth Prevention and Treatment Research Unit, Guangzhou Women & Children's Medical Center, Guangzhou Medical University, Guangzhou, China.
authors.forename: Robert E
authors.initials: RE
authors.lastname: Garfield
authors.affiliation: Department of Obstetrics and Gynecology, Preterm Birth Prevention and Treatment Research Unit, Guangzhou Women & Children's Medical Center, Guangzhou Medical University, Guangzhou, China. Electronic address: huishuliu@hotmail.com.
authors.forename: Huishu
authors.initials: H
authors.lastname: Liu
mesh_terms: D000818:Animals; D002634:Chemotaxis, Leukocyte / Q000187:drug effects* / Q000502:physiology; D016207:Cytokines / Q000378:metabolism*; D005260:Female; D007962:Leukocytes / Q000187:drug effects / Q000502:physiology; D008070:Lipopolysaccharides / Q000494:pharmacology*; D009538:Nicotine / Q000494:pharmacology*; D010920:Placenta / Q000187:drug effects* / Q000276:immunology / Q000378:metabolism; D011247:Pregnancy; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D016207:Cytokines; D008070:Lipopolysaccharides; D009538:Nicotine
keywords: Cytokine; Inflammation; Nicotine; Placenta; Pregnancy; α7-nAChR