In Vitro effect of Urban Air Particles from Buenos Aires (UAP-BA) on an asthma human epithelial cell model

ASTORT F1., DUGOUR A.2, FIGUEROA. J2, TASAT DR1.

Congreso; SETAC Latin America 11th Biennial Meeting; 2015

SETAC LA

Asthma is a complex genetic disorder characterized by chronic airway inflammation. While the involvement of immune cells, as well as proinflammatory cytokines and chemokines is well recognized, it is less appreciated that asthma is also a disease of oxidative stress. Among the many environmental factors that can induce asthma exacerbation, exposure to air pollutants is attracting greater attention. Air particulate matter is considered a major pollutant that can contribute to asthma exacerbation through cellular oxidative stress. In this sense, antioxidants, such N-Acetyl Cysteine (NAC), have been used to ameliorate oxidative stress in cell models. Previously, we characterized Urban Air Particles from downtown Buenos Aires (UAP-BA), and evaluated its effect on the respiratory tract employing in vivo and in vitro models. We demonstrated that UAP-BA are ultrafine particles with no metallic traces able to generate lung inflammation and oxidative stress. Therefore we sought to analyze the role of UAP-BA on asthma and on the oxidative pathway. The objective of this work was to analyze the effect of UAP-BA in calu-3 cells preconditioned with an asthma cellular model.UAP-BA was collected using a Mini Vol sampler (1.8 L/min). Cultured Calu-3 cells were divided in groups: a) non treated (control), b) treated with 50 ng/ml IL-1β + 100 µM H2O2 (Asthma model - Asthma), c) exposed to 25 µg/ml UAP-BA, d) Asthma exposed to 25 µg/ml UAP-BA (Asthma-UAP-BA), e) Asthma-UAP-BA treated with 5 mM NAC (Asthma-UAP-BA-NAC) for 4h. After 24h, the following parameters were evaluated: cellular viability by MTT, IL-8 by ELISA, Total reduced thiols by DTNB.No changes in cell viability were observed for any of the groups assayed (Asthma, UAP-BA, NAC or its combinations). On the contrary, as expected, IL-8 levels were increased after Asthma treatment. UAP-BA alone was not able to provoke any changes in IL-8 levels, in the Asthma-UAP-BA group, the response was exacerbated. NAC treatment partially prevented the increase of IL-8 levels induced by Asthma-UAP-BA. A slight decrease in total reduced thiols was observed when cells were exposed to Asthma or Asthma-UAP-BA. Nevertheless, this decrease was not prevented by NAC.Our data shows that UAP-BA can exacerbate the IL-8 response to Asthma in Calu-3 cells in vitro. Additionally, we found that an antioxidant prone to ameliorate this effect suggesting that the mechanism of the particle adverse effect involves at least partially oxidative stress.