Effects of Naval Aviation-Related Pressure Fluctuations on a Rodent Model of Exposure
Abstract
Episodic, repeated cockpit pressure fluctuations can occur in aircraft due to complications with the system designed to control and maintain cockpit pressurization. It is possible that these decompression/compression cycles could place aircrew at risk for a range of physiologic or cognitive performance deficits, but it is unclear if these fluctuations are severe enough to elicit these effects. This study investigated the effect of hypobaric pressure fluctuations over 25 minutes in a hypobaric chamber on respiratory function and anatomy, the formation vascular gas emboli, and biomarkers of decompression injury, behavioral changes, and alterations in neuroanatomy and neurophysiology in male Sprague Dawley rats. Transient reductions in activity levels and decrements in performance on a motor coordination task were measured in rats during exposure to 0.8 psi/sec fluctuations profiles with an initial altitude of 8,000 feet. There was no fluctuation-associated decrease in activity levels or observational metrics evaluated immediately post-exposure. No impact of fluctuations on respiratory function or anatomy was found. Ultrasound imaging during the exposure revealed no vascular gas emboli in the pulmonary artery of rats exposed to fluctuation profiles of up to 1.5 psi/sec starting at initial altitudes of 8,000 feet and 14,000 feet. Increased astrocytic activation in the hippocampus was found in rats three days following exposure to 1.5 psi/sec fluctuations. Behavioral alterations and neuroanatomical changes have been associated with pressure fluctuation exposure in a rodent model, although the specific cause of both the transient impacts on motor activity and the astrocytic activation in the hippocampus are yet to be determined. Now that exposure levels necessary to induce adverse effects have been identified, future targeted studies to identify causal mechanisms and time courses of these effects can be performed in the rodent model.
Document Details
- Document Type
- Technical Report
- Publication Date
- Mar 04, 2021
- Accession Number
- AD1124119
Entities
People
- Amber M. Braddock
- Andrew J. Keebaugh
- Brian C. Sharits
- Erin L. Roberts
- Joseph M. Brune
- Josh L. Stricker
- Joyce G. Rohan
- Karen L. Mumy
- Michelle R. Armstrong
- R. A. James
- Sanjeev L. Mathur
- Shannon H. Romer
- Shawn M. Mcinturf
Organizations
- Naval Medical Research Unit Dayton
- Oak Ridge Institute for Science and Education
- Parsons Corporation