Omega-3 fatty acids lower atrial fibrillation risk in dogs

Abstract

BACKGROUND: Dietary consumption of &#x3c9;-3 fatty acids is correlated with a reduced incidence of cardiovascular events. Here, we investigated the effect of dietary &#x3c9;-3 fatty acids on atrial fibrillation (AF) vulnerability in a canine model of AF and explored the related mechanisms. METHODS: Twenty four male beagle dogs (weight, 8-10 kg) were randomly divided into four groups: (a) sham-operated group (normal chow); (b) AF+FO [AF and normal chow supplemented with fish oil (FO): 0.6 g n-3 polyunsaturated fatty acids (&#x3c9;-3 PUFA) /kg/day]; (c) AF group (normal chow); (d) sham-operated FO group (chow supplemented with FO: 0.6 g &#x3c9;-3 PUFA/kg/day). AF was induced by rapid atrial pacing (RAP: 400 bpm for 4 weeks). Daily oral administration of FO was initiated 1 week before surgery and continued for 4 weeks post operation. RESULTS: Atrial electric remodeling was significantly attenuated and AF vulnerability were significantly reduced in AF+FO group compared to AF group. Endoplasmic reticulum (ER) stress-related protein expression levels of glucose-regulated protein78, C/EBP homologous protein, cleaved-Caspase12, and phosphorylation of protein&#xa0;kinase R-like ER kinase as well as inflammatory cytokines interleukin-1&#x3b2;, interleukin-6, tumor necrosis factor-&#x3b1; in left atrium (LA) were significantly downregulated in AF+FO group than in AF group (all p<0.05). In addition, Masson staining revealed lower extent of LA interstitial fibrosis in AF+FO group than in AF group (p<0.01). Myocardial apoptosis was also significantly reduced in AF+FO group than in AF group (p<0.05). CONCLUSIONS: Dietary &#x3c9;-3 fatty acids could significantly reduce RAP-induced AF vulnerability, possibly via attenuating myocardial ER stress, inflammation, and apoptosis in this canine model of AF.