Objectives: 

Rapid spreading of the electrical impulse throughout the heart is essential for synchronized contraction and is ensured by electrical coupling of cardiomyoctes at the gap junction connexin (Cx) channels. Abnormal myocardial Cx43 distribution, expression or phopshorylation is highly pro-arrhythmic. We hypothesise that Cx43 might be implicated in anti-arrhythmic mechanisms of cardio-protective compounds: atorvastatin, omega-3 fatty acids and red palm oil.

Materials: 

Male, adult spontaneously hypertensive rats (SHR) were treated either with omega-3 fatty acids (300mg/day/2month) or red palm oil (220mg/day/1month) and hereditary hypertriglyceridemic rats (HTG) were treated with omega-3 or atorvastatin (1.5mg/day/2month). Treated rats were compared with untreated once as well as with age-matched healthy Wistar rats. Basic characteristics of animals were registered and left ventricular tissue was examined for myocardial Cx43 distribution and expression of Cx43 mRNA and/or protein. Susceptibility of the heart to lethal arrhythmia, ventricular fibrillation (VF), was examined using isolated Langedorff-perfused heart preparation.

Results: 

Treatment of SHR and HTG rats resulted in a significant reduction of elevated blood pressure, triglycerides and blood glucose. Compared to Wistar rats the threshold to induce VF was lower and its incidence higher in SHR and HTG rat hearts, which exhibited abnormal Cx43 distribution, decreased total Cx43 expression and altered (functional) phosphorylated forms of Cx43. In contrast, attenuation of disease-related abnormalities in Cx43 distribution and expression were found in treated SHR and HTG rat hearts. It was associated with a significant increase of threshold for VF and decrease of its incidence.

Conclusions: 

Results indicate that antiarrhythmic effects of red palm oil, omega-3 FA and atorvastatin are linked with modulation of myocardial Cx43 expression and its distribution. Further studies should elucidate pathways involved in Cx43 modulation by these compounds.