Arnebiae Radix prevents atrial fibrillation in rats by ameliorating atrial remodeling and cardiac function

Arnebiae Radix, a common herbal medicine in China, is often utilized to treat blood-heat syndrome and has been reported to exert an effect on the heart.The combination of acetylcholine (Ach) and CaCl2 has been widely used to induce atrial fibrillation (AF) in animals. However, whether Arnebiae Radix displays any preventive action on Ach-CaCl2 induced AF in rats remains uncertain. In our study, we attempted to investigate the protective effects of Arnebiae Radix on Ach-CaCl2 induced AF compared to amiodarone, which was employed as the positive control.To establish the AF model, SD rats were treated with a mixture of 0.1 mL/100 g Ach-CaCl2 (60 μg/mL Ach and 10 mg/mL CaCl2) by tail vein injection for 7 days. Rats were also given a gavage of Arnebiae Radix (0.18 g/mL) one week before or concurrently with the establishment of the AF model. At the end of the experimental period, the induction, duration and timing of AF were monitored using electrocardiogram recordings. Left atrial tissues were stained to observe the level of fibrosis. Electrophysiological measurements were used to examine atrial size and function.In Ach-CaCl2-induced AF rats, Arnebiae Radix decreased AF induction, duration and susceptibility to AF. In addition, Arnebiae Radix significantly reduced atrial fibrosis and inhibited atrial enlargement induced by Ach-CaCl2. Moreover, there was an apparent improvement in cardiac function in the Arnebiae Radix-treated group.Our findings indicate that Arnebiae Radix treatment can attenuate Ach-CaCl2-induced atrial injury and serve as an effective therapeutic strategy for the treatment of AF in the future.