Low doses of urban air particles from Buenos Aires promote oxidative stress and apoptosis in mice lungs

Abstract

Air pollution consists of a wide range of gaseous and particulate pollutants. Exposure to particulate matter (PM) can cause oxidative stress within the lung, which in turn can negatively impact health. The mechanisms by which PM causes oxidative stress include the release of trace metals or organic components from the particle. Previously, we have characterized urban air particles from downtown Buenos Aires (UAP-BA) and, by using in vivo animal studies, found that they are able to generate lung inflammation. Purpose: We studied lung responses to low doses of UAP-BA (15 µg), with special emphasis on oxidative balance. Methods: We assessed cell viability, total cell number (TCN) and cell differential (CD) on bronchoalveolar lavages (BAL), oxidative metabolism in lung homogenates by tertbutylhydroperoxide-initiated chemiluminescence (CL), thiobarbituric reactive substances (TBARS), total reactive antioxidant potential (TRAP), reduced glutathione (GSH), and apoptosis in lung sections. Results: We found that low UAP-BA exposure increases TCN, modifies CD, and decreases cell viability in the BAL. In lung homogenates, TBARS and CL rose while TRAP and GSH showed no alteration when compared to controls. Occurrence of apoptosis evaluated by TUNEL assay was markedly augmented in UAP-BA exposed animals. Conclusions: Our data further implicate oxidative stress as a possible inducer of apoptosis in lungs from animals exposed to low concentrations of this urban environmental contaminant.

Keywords::

• Lungs
• Buenos Aires
• particulate matter
• oxidative stress
• apoptosis

Acknowledgements

We thank Dr. Patricia Mandalunis for her technical assistance performing the TUNEL assay.

Declaration of interests

This work was partially supported by the National University of San Martín (Grants #A053 and A097).