title: [Effect of different intermittent hypoxia patterns on interleukin-6 and interleukin-8 levels of human umbilical vein endothelial cells].
abstract: OBJECTIVE
  To investigate the effect of different patterns of intermittent hypoxia on the levels of interleukin-6 (IL-6) and interleukin-8 (IL-8) of vascular endothelial cell.
  
  
  METHODS
  The human umbilical vein endothelial cells of the line ECV304 were used to set up the cells model. The experiment cell strains contained one control group and eight experimental groups, 1 constance normoxia group (control group), 3 different intermittent hypoxia (IH) degree groups (10% O₂ group, 1.5% O₂ group, 0.5% O₂ group with 12 times/h), 4 different IH frequency groups (40 times/h, 20 times/h, 12 times/h, 9 times/h and 6 times/h with 0.5%O2). The specimen were put into a program-controlled gas delivery system with different level and frequency of IH respectively. Then enzyme linked immunosorbent assay (ELISA) was used to examine the levels of IL-6 and IL-8.
  
  
  RESULTS
  Higher level of IL-6 and IL-8 were found in 3 different IH degree groups than in control group (F were 1961.100 and 103.855 respectively, P all < 0.001). The level of IL-6 and IL-8 was gradually increased with the decreasing of IH degree. The difference of IL-6 and IL-8 levels between each two different groups in IH degree was significant (P all < 0.05). The level of IL-6 and IL-8 groups was significantly different in severe IH exposure (F were 544.396 and 149.328 respectively, P all < 0.001 in both groups). There was a trend as the IH frequency decreased, the level of IL-6 and IL-8 was tenderly increased in 20/hour group (P < 0.05), highest in 12/hour group (P < 0.05), decreased in 9/hour group (P < 0.05), and decreased further in 6/hour group (P < 0.05) in severe IH expose. There was statistical significance between each two different frequency IH groups (P < 0.05).
  
  
  CONCLUSIONS
  Intermittent hypoxia caused significant inflammatory reaction in vascular endothelial cells. The secreted level of IL-6 and IL-8 depended on the degree of hypoxia. There was a trend as the level of IH frequency decreased, the level of IL-6 and IL-8 gradually increased at first, and then decreased in the same way.
authors.affiliation: Department of Respiratory Medicine, Tianjin Medical University, General Hospital, Tianjin 300052, China.
authors.forename: Ye-Mei
authors.initials: YM
authors.lastname: Li
authors.forename: Bao-Yuan
authors.initials: BY
authors.lastname: Chen
authors.forename: Jing
authors.initials: J
authors.lastname: Feng
authors.forename: Zhen-Kuan
authors.initials: ZK
authors.lastname: Liu
authors.forename: Li-Xia
authors.initials: LX
authors.lastname: Dong
mesh_terms: D015687:Cell Hypoxia; D002460:Cell Line; D004730:Endothelium, Vascular / Q000378:metabolism*; D006801:Humans; D015850:Interleukin-6 / Q000378:metabolism*; D016209:Interleukin-8 / Q000378:metabolism*; D014471:Umbilical Veins / Q000166:cytology / Q000378:metabolism*
chemical_list: C508606:CXCL8 protein, human; C508600:IL6 protein, human; D015850:Interleukin-6; D016209:Interleukin-8