title: Hyperbaric oxygen preconditioning ameliorates blood-brain barrier damage induced by hypoxia through modulation of tight junction proteins in an in vitro model.
abstract: OBJECTIVE
  To explore the effects of hyperbaric oxygen preconditioning (HBOP) on the permeability of blood-brain barrier (BBB) and expression of tight junction proteins under hypoxic conditions in vitro.
  
  
  METHODS
  A BBB in vitro model was constructed using the hCMEC/D3 cell line and used when its trans-endothelial electrical resistance (TEER) reached 80-120 Ω · cm2 (tested by Millicell-Electrical Resistance System). The cells were randomly divided into the control group cultured under normal conditions, the group cultured under hypoxic conditions (2%O2) for 24 h (hypoxia group), and the group first subjected to HBOP for 2 h and then to hypoxia (HBOP group). Occludin and ZO-1 expression were analyzed by immunofluorescence assay.
  
  
  RESULTS
  Normal hCMEC/D3 was spindle-shaped and tightly integrated. TEER was significantly reduced in the hypoxia (P=0.001) and HBOP group (P=0.014) compared to control group, with a greater decrease in the hypoxia group. Occludin membranous expression was significantly decreased in the hypoxia group (P=0.001) compared to the control group, but there was no change in the HBOP group. ZO-1 membranous expression was significantly decreased (P=0.002) and cytoplasmic expression was significantly increased (P=0.001) in the hypoxia group compared to the control group, although overall expression levels did not change. In the HBOP group, there was no significant change in ZO-1 expression compared to the control group.
  
  
  CONCLUSIONS
  Hyperbaric oxygen preconditioning protected the integrity of BBB in an in vitro model through modulation of occludin and ZO-1 expression under hypoxic conditions.
authors.forename: Lei
authors.initials: L
authors.lastname: Hao
authors.forename: Xiuming
authors.initials: X
authors.lastname: Guo
authors.forename: Can
authors.initials: C
authors.lastname: Zou
authors.forename: Huchuan
authors.initials: H
authors.lastname: Zhou
authors.forename: Hong
authors.initials: H
authors.lastname: Tian
authors.forename: Yubo
authors.initials: Y
authors.lastname: Zhang
authors.forename: Chuan
authors.initials: C
authors.lastname: Song
authors.affiliation: Lei Liu, No. 29 Jianxin East Road, Jiangbei District, Chongqing, 400020, China, shenjingneike324@126.com.
authors.forename: Lei
authors.initials: L
authors.lastname: Liu
mesh_terms: D001812:Blood-Brain Barrier / Q000378:metabolism* / Q000473:pathology; D015687:Cell Hypoxia; D002460:Cell Line; D002462:Cell Membrane / Q000378:metabolism; D003593:Cytoplasm / Q000378:metabolism; D006801:Humans; D006931:Hyperbaric Oxygenation; D062793:Occludin / Q000378:metabolism*; D010539:Permeability; D062826:Zonula Occludens-1 Protein / Q000378:metabolism*
chemical_list: D062793:Occludin; C569042:TJP1 protein, human; D062826:Zonula Occludens-1 Protein