2 Global pollutant phenanthrene is proarrhythmic in aged mice

<h3></h3> Phenanthrene (Phe) is a polyaromatic hydrocarbon found „predominantly in fossil fuel and petroleum-based pollution. Previous research has shown that acute exposure to high concentrations of Phe is pro-arrhythmic in mice.¹ To determine the arrhythmic potential of chronic low-level exposure to Phe, 16 5-week-old mice and 16 20-month-old mice were fed 6μg/„kg Phe or vehicle control daily for 10 weeks. Repeat ECG and echocardiography measurements were collected during the exposure period. All animal work was carried out in accordance with the UK animals (scientific procedures) act 1986. Following the 10-week exposure hearts were subjected to an ex-vivo arrhythmia challenge and tissue was collected for gas chromatography mass-spectrometry and histological analysis. Preliminary analysis has revealed a proarrhythmic phenotype which resulted in an increased susceptibility to arrhythmia in aged mice. Phe significantly prolonged PR interval in aged mice (n=8, 2-way ANOVA: p&lt;0.05) and increased heart weight/body weight ratio (n=8, Mann-Whitney test, p&lt;0.05). Subsequently, 63% of aged mice exposed to Phe showed spontaneous arrhythmic activity ex vivo versus none of the control or young mice (n=8, t test: p&lt;0.05). Phe exposure significantly increased arrhythmia induction following pacing, from 17% to 75% (n=8, t test: p&lt;0.05). This difference was not present when hearts were treated with isoprenaline before pacing, suggesting bradycardia as an underlying mechanism for Phe induced arrhythmia. <h3>Reference</h3> Yaar S, <i>et al</i>. Global air pollutant phenanthrene and arrhythmic outcomes in a mouse model. <i>Environ Health Perspect</i> 2023;<b>131</b>(11):Article 117002.