title: Hypoxia training attenuates left ventricular remodeling in rabbit with myocardial infarction.
abstract: OBJECTIVE
  Previous studies showed that hypoxia preconditioning could protect cardiac function against subsequent myocardial infarction injury. However, the effect of hypoxia on left ventricular after myocardial infarction is still unclear. This study therefore aims to investigate the effects of hypoxia training on left ventricular remodeling in rabbits post myocardial infarction.
  
  
  METHODS
  ADULT MALE RABBITS WERE RANDOMLY DIVIDED INTO THREE GROUPS: group SO (sham operated), group MI (myocardial infarction only) and group MI-HT (myocardial infarction plus hypoxia training). Myocardial infarction was induced by left ventricular branch ligation. Hypoxia training was performed in a hypobaric chamber (having equivalent condition at an altitude of 4000 m, FiO214.9%) for 1 h/day, 5 days/week for four weeks. At the endpoints, vascular endothelial growth factor (VEGF) in the plasma was measured. Infarct size and capillary density were detected by histology. Left ventricular remodeling and function were assessed by echocardiography.
  
  
  RESULTS
  After the 4-week experiment, compared with the group SO, plasma VEGF levels in groups MI (130.27 ± 18.58 pg/mL, P < 0.01) and MI-HT (181.93 ± 20.29 pg/mL, P < 0.01) were significantly increased. Infarct size in Group MI-HT (29.67% ± 7.73%) was deceased remarkably, while its capillary density (816.0 ± 122.2/mm(2)) was significantly increased. For both groups MI and MI-HT, left ventricular end-diastolic and end-systolic dimensions were increased whereas left ventricular ejection fraction was decreased. However, compared with group MI, group MI-HT diminished left ventricular end-diastolic (15.86 ± 1.09 mm, P < 0.05) and end-systolic dimensions (12.10 ± 1.20 mm, P < 0.01) significantly and improved left ventricular ejection fraction (54.39 ± 12.74 mm, P < 0.05).
  
  
  CONCLUSIONS
  Hypoxia training may improve left ventricular function and reduce remodeling via angiogenesis in rabbits with MI.
authors.affiliation: Rehabilitation Medicine Center, Chinese PLA General Hospital, Beijing 100853, China ; Rehabilitation Medicine Department, Wuxi No.2 Hospital Affiliated with Nanjing Medical University, Nanjing 214002, Jiangsu Province, China.
authors.forename: Chun-Xiao
authors.initials: CX
authors.lastname: Wan
authors.affiliation: Department of Healthcare, Hainan Branch of Chinese PLA General Hospital, Sanya 572000, Hainan Province, China.
authors.forename: Yun-Feng
authors.initials: YF
authors.lastname: Lan
authors.affiliation: Rehabilitation Medicine Center, Chinese PLA General Hospital, Beijing 100853, China.
authors.forename: Hui
authors.initials: H
authors.lastname: Jiang
authors.affiliation: Rehabilitation Medicine Center, Chinese PLA General Hospital, Beijing 100853, China.
authors.forename: Jie
authors.initials: J
authors.lastname: Huang
authors.affiliation: Research and Technology Service Center, 302 Hospital of PLA, Beijing 100039, China.
authors.forename: Rui-Sheng
authors.initials: RS
authors.lastname: Li
authors.affiliation: Rehabilitation Medicine Center, Chinese PLA General Hospital, Beijing 100853, China.
authors.forename: Sheng
authors.initials: S
authors.lastname: Bi
authors.affiliation: Rehabilitation Medicine Center, the First Affiliated Hospital of Nanjing Medical University, Nanjing 210029, Jiangsu Province, China.
authors.forename: Jian-An
authors.initials: JA
authors.lastname: Li
keywords: Hypobaric hypoxia; Infarct size; Left ventricular remodelling; Myocardial infarction; Vascular endothelial growth factor