title: The anti-arrhythmic effect of chronic intermittent hypobaric hypoxia in rats with metabolic syndrome induced with fructose.
abstract: This study investigated the anti-arrhythmic effects from chronic intermittent hypobaric hypoxia (CIHH) and the cellular mechanisms in rats with metabolic syndrome. Male Sprague-Dawley rats were randomly distributed among the control, fructose-fed (fed with 10% fructose in the drinking water to induce metabolic syndrome), CIHH (42 days of hypobaric hypoxia treatment simulating an altitude of 5000 m a.s.l.: PB = 404 mm Hg, PO2 = 84 mm Hg, 6 h per day), and the CIHH plus fructose (CIHH-F) groups. In anesthetized rats, the arrhythmia score was determined after 30 min of cardiac ischemia followed by 120 min of reperfusion. Action potentials (AP) were recorded from isolated ventricular papillary muscles. The arrhythmia score was much lower in CIHH-F rats than in the fructose-fed rats. Under basic conditions, AP duration (APD) was significantly shortened in fructose-fed rats, but obviously prolonged in CIHH rats compared with that of the control rats. During ischemia, the AP amplitude, the maximal rate of rise of phase 0, APD, and resting potential, were lower in the control, fructose-fed, and CIHH-F groups, but were not changed in the CIHH rats. The lower AP during ischemia did not recover after washout for the fructose-fed rats. In conclusion, CIHH protects the heart against ischemia-reperfusion induced arrhythmia in rats with metabolic syndrome. This effect of CIHH is possibly related to baseline prolongation of the AP and attenuation of AP reduction during ischemia-reperfusion.
authors.affiliation: Department of Physiology, Hebei Medical University, Shijiazhuang 050017, China., Hebei Collaborative Innovation Center for Cardio-cerebrovascular Disease, Shijiazhuang, Hebei 050000, P.R. China.
authors.forename: Jing-Jing
authors.initials: JJ
authors.lastname: Zhou
authors.forename: Hui-Jie
authors.initials: HJ
authors.lastname: Ma
authors.forename: Yan
authors.initials: Y
authors.lastname: Liu
authors.forename: Yue
authors.initials: Y
authors.lastname: Guan
authors.forename: Leonid N
authors.initials: LN
authors.lastname: Maslov
authors.forename: De-Pei
authors.initials: DP
authors.lastname: Li
authors.forename: Yi
authors.initials: Y
authors.lastname: Zhang
mesh_terms: D000200:Action Potentials; D000532:Altitude Sickness / Q000503:physiopathology*; D000818:Animals; D001145:Arrhythmias, Cardiac / Q000209:etiology / Q000517:prevention & control*; D001273:Atmosphere Exposure Chambers; D054059:Coronary Occlusion / Q000209:etiology* / Q000503:physiopathology; D004032:Diet / Q000009:adverse effects; D004195:Disease Models, Animal; D004562:Electrocardiography; D005632:Fructose / Q000009:adverse effects; D019157:Ischemic Preconditioning, Myocardial / Q000379:methods*; D008026:Ligation; D008297:Male; D024821:Metabolic Syndrome / Q000209:etiology / Q000503:physiopathology / Q000628:therapy*; D015428:Myocardial Reperfusion Injury / Q000209:etiology / Q000503:physiopathology / Q000517:prevention & control*; D010210:Papillary Muscles / Q000503:physiopathology; D011897:Random Allocation; D017207:Rats, Sprague-Dawley; D013997:Time Factors
chemical_list: D005632:Fructose
keywords: action potential; chronic intermittent hypobaric hypoxia; hypoxie hypobare intermittente chronique; ischemia–reperfusion; metabolic syndrome; muscle papillaire; papillary muscle; potentiel d’action; syndrome métabolique, ischémie–reperfusion