Oxidative damage induced in A549 cells by physically and chemically characterized air particulate matter (PM_2.5) collected in Abidjan, Côte d'Ivoire

Abstract

Exposure to high levels of air pollution particulate matter (PM) is strongly associated with increased pulmonary morbidity and mortality. However, the underlying mechanisms of action whereby PM cause adverse health effects are still unclear. In developing countries, like in the sub-Saharian region of Africa, people are often exposed to high PM levels. Hence, three PM(2.5) samples were collected in the District of Abidjan (Côte d'Ivoire), under rural, urban or industrial influences. Their most toxicologically relevant physical and chemical characteristics were determined--thereby showing that most of them were equal or smaller than 2.5 microm--and the influence of both natural (Ca, Na, Mg, Ti, etc.) and anthropic (Al, Fe, Mn, Cr, Pb, Zn, Cu, Ni, benzene and its derivatives, paraffins, etc.) emission sources. The toxicity induced by the three PM samples was studied through 5-bromodeoxyuridine incorporation to DNA, mitochondrial dehydrogenase activity and extracellular lactate dehydrogenase activity. Hence, effect concentrations at 10 and 50% (EC(10) and EC(50), respectively) were as follows: (i) rural PM--EC(10) = 5.91 microg cm(-2) and EC(50) = 29.55 microg cm(-2); (ii) urban PM--EC(10) = 5.45 microg cm(-2) and EC(50) = 27.23 microg cm(-2); and (iii) industrial PM--EC(10) = 6.86 microg cm(-2) and EC(50) = 34.29 microg cm(-2). Moreover, PM-induced oxidative damage in A549 cells was observed through the induction of lipid peroxidation, the alteration of superoxide dismutase activity, and the disruption of glutathione status. Both the transition metals and the organic chemicals within the three collected PM samples under study might be involved in the oxidative damage and, therefore, the toxicity they induced in A549 cells.

Oxidative Stress and Air Pollution Exposure

“…Some DEPs consist of a carbon core or organic droplets with adsorbed organic compounds, such as PAH, quinines, and redox-active metals. The capacity of DEPs to induce oxidative stress is largely related to these adsorbed components [60, 61]. …”

Particulate matter 2.5 damages skin cells by inducing oxidative stress, subcellular organelle dysfunction, and apoptosis

“…AhR activation by PAHs upregulates the expression of cytochrome P450 (CYP1A1) involved in the metabolism of xenobiotics (Vogel et al 2016) and promotes generation of intracellular reactive oxygen species (ROS) (Costa et al 2010). Accumulated evidence indicates that oxidative stress is a common mechanism of PM 2.5 -induced damage (Gualtieri et al 2012; Kouassi et al 2010). Recently, the effect of PM 2.5 on the skin has attracted attention of both clinical dermatologists and basic scientists (Han et al 2016; Li et al 2017), who recognized ambient PM 2.5 as a crucial risk factor in skin diseases.…”

Physico-chemical characterization of African urban aerosols (Bamako in Mali and Dakar in Senegal) and their toxic effects in human bronchial epithelial cells: description of a worrying situation

“…Only a few studies have been conducted in developing countries such as in Africa [8,9]. This is in spite of the very high levels of pollution (both for gases – NO 2 , SO 2 and particles) observed in African cities being at same levels as in Asian megacities [10-13] and well above WHO (world health organization) international norms.…”