title: Different correlation of sphingosine-1-phosphate receptor 1 with receptor activator of nuclear factor kappa B ligand and regulatory T cells in rat periapical lesions.
abstract: BACKGROUND
  Sphingosine-1-phosphate receptor 1 (S1P1) is crucial for regulation of immunity and bone metabolism. This study aimed to investigate the expression of S1P1 in rat periapical lesions and its relationship with receptor activator of nuclear factor kappa B ligand (RANKL) and regulatory T (Treg) cells.
  
  
  METHODS
  Periapical lesions were induced by pulp exposure in the first lower molars of 55 Wistar rats. Thirty rats were killed on days 0, 7, 14, 21, 28, and 35, and their mandibles were harvested for x-ray imaging, micro-computed tomography scanning, histologic observation, immunohistochemistry, enzyme histochemistry, and double immunofluorescence analysis. The remaining 25 rats were killed on days 0, 14, 21, 28, and 35, and mandibles were harvested for flow cytometry.
  
  
  RESULTS
  The volume and area of the periapical lesions increased from day 0 to day 21 and then remained comparably stable after day 28. S1P1-positive cells were observed in the inflammatory periapical regions; the number of S1P1-positive cells peaked at day 14 and then decreased from day 21 to day 35. The distribution of S1P1-positive cells was positively correlated with the dynamics of RANKL-positive cells but was negatively correlated with that of Treg cells.
  
  
  CONCLUSIONS
  S1P1 expression was differentially correlated with RANKL and Treg cell infiltration in the periapical lesions and is therefore a contributing factor to the pathogenesis of such lesions.
authors.affiliation: The State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST) and Key Laboratory of Oral Biomedicine Ministry of Education, School and Hospital of Stomatology, Wuhan University, Wuhan, China.
authors.forename: Lan
authors.initials: L
authors.lastname: Xiao
authors.affiliation: The State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST) and Key Laboratory of Oral Biomedicine Ministry of Education, School and Hospital of Stomatology, Wuhan University, Wuhan, China.
authors.forename: Lingxin
authors.initials: L
authors.lastname: Zhu
authors.affiliation: The State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST) and Key Laboratory of Oral Biomedicine Ministry of Education, School and Hospital of Stomatology, Wuhan University, Wuhan, China.
authors.forename: Shasha
authors.initials: S
authors.lastname: Yang
authors.affiliation: The State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST) and Key Laboratory of Oral Biomedicine Ministry of Education, School and Hospital of Stomatology, Wuhan University, Wuhan, China.
authors.forename: Dongqi
authors.initials: D
authors.lastname: Lei
authors.affiliation: Institute of Health and Biomedical Innovation, Queensland University of Technology, Kelvin Grove Campus, Brisbane, Australia.
authors.forename: Yin
authors.initials: Y
authors.lastname: Xiao
authors.affiliation: The State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST) and Key Laboratory of Oral Biomedicine Ministry of Education, School and Hospital of Stomatology, Wuhan University, Wuhan, China. Electronic address: phs301@vip.163.com.
authors.forename: Bin
authors.initials: B
authors.lastname: Peng
mesh_terms: D000818:Animals; D005260:Female; D005434:Flow Cytometry; D010010:Osteoclasts / Q000378:metabolism; D010483:Periapical Diseases / Q000378:metabolism* / Q000473:pathology; D053245:RANK Ligand / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D049349:Receptors, Lysosphingolipid / Q000378:metabolism*; D050378:T-Lymphocytes, Regulatory / Q000378:metabolism*
chemical_list: D053245:RANK Ligand; D049349:Receptors, Lysosphingolipid
keywords: Bone resorption; RANKL; S1P(1); osteoclast; periapical lesions; regulatory T cells