The effect of melatonin on the barrier properties of human primary aortic endothelial and human aortic smooth muscle cells based on the real-time cell electric impedance sensing system

Abstract Introduction: Experimental studies have confirmed the potential vasculoprotective effects of melatonin. The aim of the study was to evaluate the influence of melatonin and its modulative role on 7-ketocholesterol-induced changes in human aortic endothelial cells (HAECs) and human aortic smooth muscle cells (HuAoSMCs). Materials and methods: The real-time cell electric impedance sensing (xCELLigence) system was used to measure cell impedance, while flow cytometry was employed to assess viability and apoptosis. Results: It was found that melatonin did not change the impedance and viability of HuAoSMCs, nor did it inhibit their 7-ketocholesterol- induced apoptosis. Melatonin decreased the impedance of HAECs. However, this effect was not attributed to cell apoptosis. In addition, it did not prevent the 7-ketocholesterol-induced decrease in HAEC impedance. Nevertheless, pretreatment with melatonin at concentrations of 10 nM and 100 nM attenuated the apoptosis caused by 7-ketocholesterol. Conclusions: This study confirmed the toxic effect of 7-ketocholesterol on primary human vascular wall cells, using 2 independent methods. We have demonstrated that melatonin has no barrier-protective effect, but low concentrations of melatonin may counteract the toxic effect of 7-ketocholesterol on HAECs through the inhibition of apoptosis. Melatonin has no significant effect on the impedance and viability of HuAoSMCs.