The anti-arrhythmic effect of chronic intermittent hypobaric hypoxia in rats with metabolic syndrome induced with fructose.
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.
['Zhou|Jing-Jing|JJ|', 'Ma|Hui-Jie|HJ|', 'Liu|Yan|Y|', 'Guan|Yue|Y|', 'Maslov|Leonid N|LN|', 'Li|De-Pei|DP|', 'Zhang|Yi|Y|']
D000200:Action Potentials D000532:Altitude Sickness D000818:Animals D001145:Arrhythmias, Cardiac D001273:Atmosphere Exposure Chambers D054059:Coronary Occlusion D004032:Diet D004195:Disease Models, Animal D004562:Electrocardiography D005632:Fructose D019157:Ischemic Preconditioning, Myocardial D008026:Ligation D008297:Male D024821:Metabolic Syndrome D015428:Myocardial Reperfusion Injury D010210:Papillary Muscles D011897:Random Allocation D017207:Rats, Sprague-Dawley D013997:Time Factors
chronic intermittent hypobaric hypoxia metabolic syndrome action potential papillary muscle hypoxie hypobare intermittente chronique ischemia–reperfusion muscle papillaire potentiel d’action syndrome métabolique, ischémie–reperfusion