title: The protective effects of chronic intermittent hypobaric hypoxia pretreatment against collagen-induced arthritis in rats.
abstract: OBJECTIVE
  To explore the immunological mechanisms underlying the effect of chronic intermittent hypobaric hypoxia (CIHH) pretreatment on collagen-induced arthritis (CIA) in rat.
  
  
  METHODS
  Fifty-four adult male Sprague-Dawley rats were used in the experiment. Arthritis in CIA rats (n=18) was induced by injection of collagen. The CIHH+CIA rats (n=18) were treated with CIHH (simulated 3000 m altitude, 5 hours per day for 28 days, PO2=108.8 mmHg) before CIA. The control rats (n=18) were not given any treatment.
  
  
  RESULTS
  (1) Incidence rate of CIA in CIHH+CIA rats was significantly lower than that in CIA rats (P<0.05). (2) The paw thickness and arthritis index (AI) value in CIHH+CIA rats were lower than those in CIA rats (P<0.05). (3) The hyperplasia with inflammatory infiltration in synovial tissue of joints in CIHH+CIA rats was much alleviative compared with CIA rats. (4) TNF-α, IFN-γ, IL-4 and IL-17 in synovial tissue of joint and serum in CIHH+CIA rats were decreased compared with CIA rats (P<0.05). (5) The number of CD4-positive T-lymphocytes and the ratio of CD4/CD8 T-lymphocytes in peripheral blood in CIHH+CIA rats were lower than those in CIA rats (P<0.05). (6) The protein expression of HIF-1α and NF-κB in synovial tissue of joint in CIHH+CIA rats was decreased compared with CIA rats (P<0.05).
  
  
  CONCLUSIONS
  CIHH pretreatment has a protective effect against collagen-induced arthritis in rat through down-regulation of HIF-1α and NF-κB, inhibition of inflammatory cytokines TNF-α and IL-17, and balance in CD4/CD8 and Th1/Th2 T lymphocytes.
authors: Department of Physiology, Hebei Medical University, Shijiazhuang, 050017 China ; Department of Clinical Laboratory, The Second Hospital of Hebei Medical University, Shijiazhuang, 050017 China.
authors: Min
authors: M
authors: Shi
authors: Department of Physiology, Hebei Medical University, Shijiazhuang, 050017 China.
authors: Fang
authors: F
authors: Cui
authors: Department of Immune and Rheumatism, The Second Hospital of Hebei Medical University, Shijiazhuang, 050017 China.
authors: Ai-Jing
authors: AJ
authors: Liu
authors: Department of Physiology, Hebei Medical University, Shijiazhuang, 050017 China.
authors: Hui-Jie
authors: HJ
authors: Ma
authors: Department of Physiology, Hebei Medical University, Shijiazhuang, 050017 China.
authors: Ming
authors: M
authors: Cheng
authors: Department of Immunology, Hebei Medical University, Shijiazhuang, 050017 China.
authors: Shu-Xia
authors: SX
authors: Song
authors: Department of Physiology, Hebei Medical University, Shijiazhuang, 050017 China.
authors: Fang
authors: F
authors: Yuan
authors: Department of Critical Care, The University of Texas, MD Anderson Cancer Center, Houston, TX 77030 USA.
authors: De-Pei
authors: DP
authors: Li
authors: Department of Physiology, Hebei Medical University, Shijiazhuang, 050017 China ; Hebei Key Laboratory of Medical Biotechnology, Shijiazhuang, 050017 China ; Hebei Collaborative Innovation Center for Cardio-Cerebrovascular Disease, Shijiazhuang, Hebei 050000 PR China.
authors: Yi
authors: Y
authors: Zhang
keywords: Chronic intermittent hypobaric hypoxia; HIF-1α; NF-κB; Rat; Rheumatoid arthritis; T lymphocytes; Th1/Th2