title: Alterations of Thymic Epithelial Cells in Lipopolysaccharide-induced Neonatal Thymus Involution.
abstract: BACKGROUND
  Vascular endothelial growth factor (VEGF) in the thymus was mainly produced by the thymic epithelial cells (TECs), the predominant component of the thymic microenvironment. The progression of TECs and the roles of VEGF in the neonatal thymus during sepsis have not been reported. This study aimed to explore the alterations of TECs and VEGF level in the neonatal thymus involution and to explore the possible mechanisms at the cellular level.
  
  
  METHODS
  By establishing a model of clinical sepsis, the changes of TECs were measured by hematoxylin-eosin staining, confocal microscopy, and flow cytometry. Moreover, the levels of VEGF in serum and thymus were assessed based on enzyme-linked immunosorbent assay and Western blotting.
  
  
  RESULTS
  The number of thymocytes and TECs was significantly decreased 24 h after lipopolysaccharide (LPS) challenge, (2.40 ± 0.46)×10 7 vs. (3.93 ± 0.66)×10 7 and (1.16 ± 0.14)×10 5 vs. (2.20 ± 0.19)×10 5 , P < 0.05, respectively. Cortical TECs and medullary TECs in the LPS-treated mice were decreased 1.5-fold and 3.9-fold, P < 0.05, respectively, lower than those in the controls. The number of thymic epithelial progenitors was also decreased. VEGF expression in TECs was down-regulated in a time-dependent manner.
  
  
  CONCLUSIONS
  VEGF in thymic cells subsets might contribute to the development of TECs in neonatal sepsis.
authors.forename: Yong-Jie
authors.initials: YJ
authors.lastname: Zhou
authors.forename: Hua
authors.initials: H
authors.lastname: Peng
authors.forename: Yan
authors.initials: Y
authors.lastname: Chen
authors.affiliation: Department of Pediatrics, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei 430022, China.
authors.forename: Ya-Lan
authors.initials: YL
authors.lastname: Liu
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D002478:Cells, Cultured; D004847:Epithelial Cells / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism; D008070:Lipopolysaccharides / Q000633:toxicity*; D051379:Mice; D013950:Thymus Gland / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism; D042461:Vascular Endothelial Growth Factor A / Q000378:metabolism
chemical_list: D008070:Lipopolysaccharides; D042461:Vascular Endothelial Growth Factor A