Acute Effects of Oral Exposure to Middle East PM 10 Dust on Systemic Parameters in Laboratory Mouse (Mus musculus)

Health effect particularly desert storm pneumonitis in U.S. military personnel deployed in Iraq and other parts of the Middle East reported as a result of exposure to desert sand or desert dust, a major component of ambient particulate matter (PM). Further, literature reported adverse pulmonary and systemic health effects following inhalation of PM-associated silica, metal and microorganisms, we believe that desert dust oral exposure will result in the circulation and an increased bioavailability of PM-associated components, resulting in a significant systemic response. The present study was to examine the acute effects of desert sand oral exposure on systemic inflammation and injury in mice and establish if PM10 has significant health related effects on tissues where it accumulates at the cellular level. In this study, mice were exposed to Middle East dust of thoracic PM fraction (PM10) in saline or saline alone via oral gavage for one time. At 4 hr and 24 hr following gavage administration, animals were euthanized for tissue reactive oxygen species (ROS) analyses. We used ROS scavenger phenyl-N-tert-butylnitrone (PBN) for another set of mice, administered 30 minutes prior to sacrifice to trap radical species for electron paramagnetic resonance (EPR) spectroscopy. As a positive control for ROS formation, mice were orally given endotoxin (LPS), which generates elevated ROS in liver within four hours of exposure. At both time points, EPR spectroscopy analyses were carried out on the liver. In addition, metal analysis and bioavailability in each systemic organ such as heart, liver, skin, brain and other major organs were performed by inductively coupled plasma mass spectroscopy (ICP-MS). The results of these studies may provide further insight into the cause of clinical symptoms, such as severe acute pneumonitis, chronic systemic symptoms or even Gulf War Illness, in deployed or previously deployed war fighters.