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Abstract(s)
A aplicação tópica de protetores solares contra os efeitos nocivos da radiação ultravioleta é a proteção preferida a nível mundial. Atualmente, o octilmetoxicinamato (OMC) é um dos filtros ultravioleta-B mais utilizado na composição dos protetores solares. Estudos recentes demostraram que o OMC pode comportar-se como um disruptor endócrino, mas a nível vascular apenas um estudo inicou a avaliação dos seus efeitos.
Neste sentido, o objetivo geral do presente trabalho consistiu no estudo do efeito do OMC no tónus arterial e na análise dos possíveis mecanismos envolvidos neste efeito. Para atingir este objetivo foram delineados os seguintes objetivos específicos: 1) Realizar com sucesso o isolamento e cultura de células musculares lisas da artéria umbilical humana (HUASMC); 2) Analisar o efeito do OMC em artérias umbilicais humanas (HUA) sem endotélio, e em HUASMC; 3) Analisar possíveis mecanismos envolvidos no efeito do OMC em HUA, principalmente o envolvimento dos nucleótidos cíclicos e dos canais de cálcio.
Os resultados demonstraram que o OMC exerce um efeito relaxante arterial rápido (não genómico) e independente de endotélio. Também provoca relaxamento a nível das HUASMC. O mecanismo de ação do OMC pode ser, em parte, semelhante ao dos estrogénios, envolvendo a ativação da guanil ciclase solúvel, com aumento dos níveis de cGMP. Para além disso, este mecanismo não envolve a ativação dos canais de cálcio do tipo L. Estudos adicionais são necessários para compreender melhor o mecanismo de ação do OMC a nível vascular.
The topical application of sunscreens against the harmful effects of ultraviolet radiation is the preferred protection worldwide. Octylmethoxycinnamate (OMC) is one the most widely used ultraviolet-B filter in the composition of sunscreens. Recent studies have shown that the OMC behaves like an endocrine disruptor, but at vascular level only one study initiated the evaluation of its effects. In this sense, the aim of the present study was to investigate the effect of the OMC on the arterial tonus and the analysis of the possible mechanisms involved in this effect. To achieve this prupose, specific objectives were outlined: 1) To perform the isolation and culture of the human umbilical artery smooth muscle cells (HUASMC); 2) To analyse the effect of the OMC in human umbilical arteries (HUA) without endothelium, and in HUASMC; 3) To analyse the mechanism involved in the OMC effect on HUA, mainly the involvement of cyclic nucleotides and calcium channels. Our results demonstrated that the OMC exerts a rapid (non-genomic) relaxing arterial effect and independent of endothelium. It also causes a relaxation at HUASMC level. The mechanism of action of the OMC can be, in part, similar to that of oestrogens, involving the activation of soluble guanyl cyclase, with increase of the cGMP levels. In addition, it does not go through an activation of the L-type calcium channels. Further studies are needed to better understand the mechanism of action of the OMC at vascular level.
The topical application of sunscreens against the harmful effects of ultraviolet radiation is the preferred protection worldwide. Octylmethoxycinnamate (OMC) is one the most widely used ultraviolet-B filter in the composition of sunscreens. Recent studies have shown that the OMC behaves like an endocrine disruptor, but at vascular level only one study initiated the evaluation of its effects. In this sense, the aim of the present study was to investigate the effect of the OMC on the arterial tonus and the analysis of the possible mechanisms involved in this effect. To achieve this prupose, specific objectives were outlined: 1) To perform the isolation and culture of the human umbilical artery smooth muscle cells (HUASMC); 2) To analyse the effect of the OMC in human umbilical arteries (HUA) without endothelium, and in HUASMC; 3) To analyse the mechanism involved in the OMC effect on HUA, mainly the involvement of cyclic nucleotides and calcium channels. Our results demonstrated that the OMC exerts a rapid (non-genomic) relaxing arterial effect and independent of endothelium. It also causes a relaxation at HUASMC level. The mechanism of action of the OMC can be, in part, similar to that of oestrogens, involving the activation of soluble guanyl cyclase, with increase of the cGMP levels. In addition, it does not go through an activation of the L-type calcium channels. Further studies are needed to better understand the mechanism of action of the OMC at vascular level.
Description
Keywords
Artéria Umbilical Humana Células Musculares Lisas Disruptor Endócrino Octilmetoxicinamato Relaxação