Omacor Protects Normotensive and Hypertensive Rats Exposed to Continuous Light from Increased Risk to Malignant Cardiac Arrhythmias.

Tamara Egan Benova,Katarina Andelova,Vladimir Knezl,Narcis Tribulova,Barbara Szeiffova Bacova,Jitka Zurmanova,Csilla Viczenczova

doi:10.3390/md19120659

Tamara Egan Benova, Katarina Andelova + Show 5 more

Open Access

https://doi.org/10.3390/md19120659

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Abstract

Light pollution disturbs circadian rhythm, and this can also be deleterious to the heart by increased susceptibility to arrhythmias. Herein, we investigated if rats exposed to continuous light had altered myocardial gene transcripts and/or protein expression which affects arrhythmogenesis. We then assessed if Omacor® supplementation benefitted affected rats. Male and female spontaneously hypertensive (SHR) and normotensive Wistar rats (WR) were housed under standard 12 h/12 h light/dark cycles or exposed to 6-weeks continuous 300 lux light for 24 h. Half the rats were then treated with 200 mg/100 g b.w. Omacor®. Continuous light resulted in higher male rat vulnerability to malignant ventricular fibrillation (VF). This was linked with myocardial connexin-43 (Cx43) down-regulation and deteriorated intercellular electrical coupling, due in part to increased pro-inflammatory NF-κB and iNOS transcripts and decreased sarcoplasmic reticulum Ca2+ATPase transcripts. Omacor® treatment increased the electrical threshold to induce the VF linked with amelioration of myocardial Cx43 mRNA and Cx43 protein levels and the suppression of NF-κB and iNOS. This indicates that rat exposure to continuous light results in deleterious cardiac alterations jeopardizing intercellular Cx43 channel-mediated electrical communication, thereby increasing the risk of malignant arrhythmias. The adverse effects were attenuated by treatment with Omacor®, thus supporting its potential benefit and the relevance of monitoring omega-3 index in human populations at risk.

Highlights

Light pollutions and continuous light associated with melatonin deficiency disturb circadian rhythm [1,2], and constant light hampers pineal gland function and abolishes approximately 90% of nocturnal melatonin production [3]
Systolic blood pressure (SBP) was increased in both male and female spontaneously hypertensive (SHR) rats but not in the Wistar rats (WR). Both WR and SHR rats exposed to continuous light for 6 weeks had significant SBP increase, and this was less pronounced in the females
In order to test the anti-inflammatory effects of Omacor®, we examined the gene transcript of the kappa-light-chain-enhancing nuclear factor for activated B cells (NF-κB) which is a central inflammatory mediator down-regulating Cx43 [16], thereby promoting occurrence of malignant cardiac arrhythmias

Summary

Introduction

Light pollutions and continuous light associated with melatonin deficiency disturb circadian rhythm [1,2], and constant light hampers pineal gland function and abolishes approximately 90% of nocturnal melatonin production [3]. Interventions which prevent and/or attenuate Cx43 disorders can provide benefits [14,19], and it is important here that the unique properties of omega-3 polyunsaturated fatty acids, such as Omacor® are permanent subjects of investigation in the protection of cardiovascular health and prevention of cardiac arrhythmias [20]. In this context it should be emphasized that Omacor® used in this study exerts relevance to marine biosciences due to a marine-originated, dedicated plant that is a source of the high content of eicosapentanoic acid (EPA) and docosahexanoic acid (DHA). We tested our hypothesis that supplementing rats with marine drug formula Omacor® is cardioprotective and preserves Cx43 in ‘light smog’

Results

Animals and Experimental Design

Examination of Vulnerability of the Heart to VF

Statistical Analysis

Conclusions