title: Protective effects of apocynin on atrial electrical remodeling and oxidative stress in a rabbit rapid atrial pacing model.
abstract: It has been proposed that apocynin might be used in the prevention and management of atrial fibrillation (AF). The purpose of this study was to investigate the effects of apocynin on atrial electrical remodeling and oxidative stress promoted by rapid atrial pacing (RAP) in rabbits. New Zealand white rabbits were subjected to RAP with or without apocynin treatment. Serial electrophysiological studies (EPS) were performed at baseline and every half hour after RAP onset. Superoxide dismutase (SOD) and lactate dehydrogenase (LDH) activities and Ca²⁺ content in tissue homogenates of both atria were assayed after EPS. In the RAP group but not in the sham-operated and RAP with apocynin groups, atrial effective refractory periods (AERPs) at cycle length of 200 and 150 ms shortened most clearly by 20.8 ± 10.2 ms at 3 h (P < 0.001) and by 12.8 ± 11.1 ms at 2 h (P < 0.05) respectively, and AERP rate adaptation decreased to minus values. Higher AF inducibility (66.7%) and longer AF duration (an average of 37.8 min) were presented in the RAP group. Compared with the other groups, SOD activity was lower, and LDH activity and Ca²⁺ content were higher in the RAP group. Similar differences were not found between the sham-operated and the RAP with apocynin treatment groups. These data show that apocynin attenuates the development of atrial electrical remodeling in a short period of 3-hour RAP, and reduces RAP-mediated inducibility and duration of AF in this model.
authors.affiliation: Department of Cardiology, Chinese PLA General Hospital, Beijing 100853 and Medical School, Nankai University, Tianjin 300071, People's Republic of China.
authors.forename: De-Xian
authors.initials: DX
authors.lastname: Zhang
authors.forename: Kai
authors.initials: K
authors.lastname: Ren
authors.forename: Yuan
authors.initials: Y
authors.lastname: Guan
authors.forename: Yu-Tang
authors.initials: YT
authors.lastname: Wang
authors.forename: Zhao-Liang
authors.initials: ZL
authors.lastname: Shan
mesh_terms: D000098:Acetophenones / Q000494:pharmacology / Q000627:therapeutic use*; D000818:Animals; D001281:Atrial Fibrillation / Q000188:drug therapy* / Q000503:physiopathology; D064752:Atrial Remodeling / Q000187:drug effects*; D002118:Calcium / Q000378:metabolism; D002304:Cardiac Pacing, Artificial; D005260:Female; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D008297:Male; D019255:NADPH Oxidases / Q000037:antagonists & inhibitors / Q000502:physiology; D018384:Oxidative Stress / Q000187:drug effects*; D011817:Rabbits; D012032:Refractory Period, Electrophysiological / Q000187:drug effects; D013482:Superoxide Dismutase / Q000378:metabolism
chemical_list: D000098:Acetophenones; C056165:acetovanillone; D007770:L-Lactate Dehydrogenase; D013482:Superoxide Dismutase; D019255:NADPH Oxidases; D002118:Calcium