Mouse Model of Atrial Fibrillation

A total of 60 C57BL/6 J male mice (8-week-old) were obtained from the Experimental Animal Center of Medical School, Xi’an Jiaotong University. AF model was established by a mixture of Ach (66 μg/kg; Shanghai Macklin Biochemical Co., Ltd., Shanghai, China) and CaCl₂ (10 mg/kg; Shanghai Macklin Biochemical Co., Ltd., Shanghai, China) by tail vein injection (i.v.) for 3 weeks [27 –29 (link)]. The mice were concurrently treated with specific CXCR4 antagonist AMD3100 (ref [30 (link)].) (6 mg/kg; Topscience, Shanghai, China) or vehicle (normal saline) by intraperitoneal injections (i.p.) for 3 weeks [31 , 32 (link)]. Specifically, the study included the following treatment groups: control (n = 15), AF model (Ach-CaCl₂; n = 15), AF model + AMD3100 (Ach-CaCl₂+ AMD3100; n = 15), and AMD3100 alone (n = 15). 3 weeks later, echocardiography and electrophysiological examination were performed before tissue sampling. The animal study was approved by the Institutional Ethics Committee for Animal Experiments of Xi’an Jiaotong University. All procedures conformed to the Guide for the Care and Use of Laboratory Animals.