Morphometric Analysis of Alveolar Responses of F344 Rats to Subchronic Inhalation211 of Nitric Oxide

摘要

Nitric oxide (NO)(sup star), the principal airborne pollutant generated from211u001ecombustion processes such as gas stoves, tobacco smoke, and burning of fossil 211u001efuels, is being tested as a therapeutic agent in clinical trials. A prior 211u001emorphometric study of rats exposed for 9 weeks to 0.5 parts per million (ppm) NO 211u001edemonstrated focal degeneration of the alveolar interstitium and increased 211u001enumbers of fenestrated alveolar septa (Mercer et al. 1995). The limited size and 211u001edistribution of defects in this NO exposure did not alter alveolar surface area 211u001eor other morphometric indicators of lung function, but were of interest as the 211u001eresponses to inhaled NO appeared to differ from those produced by other oxidants 211u001esuch as ozone (O3) and nitrogen dioxide (NO2). Nitric oxide exposures at the same 211u001econcentration and duration as prior morphometric studies of O3 and NO2 were 211u001enecessary in order to make a comparison. This was the purpose of the current 211u001estudy in which F344 rats were exposed for 6 weeks to air, 2ppm NO, or 6 ppm NO.