Burn Pit Emission and Respirable Sand Exposures in Rats: NMR-Based Urinary Metabolomic Assessment
Technical Report,01 Nov 2015,06 Apr 2018
Henry M. Jackson Foundation for the Advancement of Military Medicine Wright-Patterson AFB United States
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The present study, utilizing a rat model, investigated the unusual pulmonary morbidity that has been reported in military personnel deployed to the Middle East. It has been hypothesized that these adverse health effects are caused by inhalation exposure to combustion smoke emissions emitted from open burning of mixed solid waste burn pit emissions mixed with particulate matter blowing desert sand in the theatre of operation. This study involved four experimental animal groups over a 37-day protocol involving inhalation exposure to clean air controls, aerosol sand for 20 days sand alone, burn pit emissions for 5 days emissions alone, or sand followed by burn pit emissions combined exposure. A cohort of rats provided urine samples at specific times during the 127-day protocol. Overall, NMR analysis of rat urine indicated that the largest effect on urinary metabolite profiles was associated with time. This finding was observed for both the control group and experimental exposure groups. It was also observed that the greatest difference in urine metabolite profiles occurred during the exposure timeframe day 1-38 and the least during the recovery period day 39-97. However, the effects due to exposure emission and sand plus emission on urinary metabolite profiles became more evident when NMR data was evaluated using a paired analysis at day 33, which is the acclimation time point following sand exposure and preceding the emissions exposure protocol. Results from this study indicated that stress appeared to be a major contributing factor to the changes observed in urinary metabolite profiles during this experimental exposure protocol to sand and burn pit emissions, but minor effects due to exposures could be discerned through careful analyses of the data.