Reduce Of Atrial Remodeling Of Rapid Atrial Pacing Pig By Inhibition Of Renin-Angiotensin System With Telmisartan

Objective: To investigate the effects of telmisartan on rapid atrial pacing pig left atrial remodeling and renin angiotensin aldosterone system. Methods: 18 healthy pigs were randomly divided into sham operation group (sham group), rapid atrial pacing group (rap group), angiotensin angiotensin II receptor inhibitor group (pacing + telmisartan, ARB group), and each group had 6 heads. Rapid pacing atrial (500 beats/min) of rap group and ARB group for 2 weeks, while install pacemaker (AOO) of sham group without pacing stimuli. 2 weeks later, left atrial myocardium was collected, and collagen was detected by Masson staining. The protein expression of TGF-beta 1, ACE2, p-ERK1/ERK2, ERK1/ERK2 and collagen-I was detected by Western-blot test. The Ang1-7 expression was detected by ELISA test. The mRNA expression of TGF-beta 1, ACE2 and ERK2 was detected by RT-PCR test. Results: 1 Compared with Sham group, expression of collagen positive staining and collagen-I increased obviously of RAP group, while compared with RAP group, expression of collagen positive staining and collagen-I decreased obviously of ARB group. 2. Compared with Sham group, protein expression of TGF-beta 1, p-ERK1/ERK2, ERK1/ERK2 and mRNA expression of TGF-beta 1, ERK2 increased (P<0.05), protein and mRNA expression of ACE2 decreased (P<0.05), and Ang1-7 expression decreased of RAP group. While compared with RAP group, protein expression of TGF-beta 1, p-ERK1/ERK2, ERK1/ERK2 and mRNA expression of TGF-beta 1, ERK2 decreased (P<0.05), protein and mRNA expression of ACE2 increased (P<0.05), and Ang1-7 expression increased of ARB group. Conclusion: Telmisartan can reduce atrial fibrosis of rapid pacing pig, and the mechanism may by increase of ACE2 to promote Ang1-7 synthesis, inhibition of TGF-beta 1-ERK pathway activation, to effectively inhibit matrix formation and maintenance of atrial fibrillation (AF).