Changes Of Notch-1 Expression In Sinoatrial Node Fat Pad Of Dogs With Chronic Atrial Fibrillation

Objective: To study the expression of Notch-1 protein and the content of Notch-1and NICD in sinoatrial node fat pad(SAN-FP)plexus of chronic atrial fibrillation dogs based on the establishment of left atrial fibrillation model induced by chronic pacing,and to clarify the close relationship between Notch signaling pathway of SAN-FP plexus and the occurrence and development of atrial fibrillation.Methods: Healthy beagle dogs weighing 18(+2.66 kg),aged 7-9 years old,were male and female.Animal quality is a first-class standard.The design and implementation of the experiment were approved by the Animal Ethics Committee.The experimental animals were randomly divided into two groups.The sham-operated group(n = 5)underwent minimally invasive thoracotomy without pacemaker implantation.Atrial fibrillation group(n = 5): minimally invasive thoracotomy with pacemaker implantation in left atrial appendage for 8 W.Results: Atrial fibrillation was successfully induced by rapid pacing of left atrial appendage in atrial fibrillation group.The expression of Notch-1 protein was significantly increased in AF group compared with sham-operated group(P < 0.05),and there was no significant difference in baseline levels of Notch-1 and NICD between SAN-FP and sham-operated group(P > 0.05).After 8 weeks,Notch-1 and NICD levels in AF group were significantly higher than those in sham-operated group(P < 0.05).Conclusion: Notch-1 may be expressed in SAN-FP plexus at different stages of atrial fibrillation during the development of atrial fibrillation.After binding with ligands,Notch-1 is activated in the form of NICD and then affects the target gene.