Elastase-treated Rats Research Articles

Pulmonary function in elastase-treated guinea pigs and rats exposed to ammonium sulfate or ammonium nitrate aerosols

Three weeks following intratracheal instillations of elastase dissolved in saline, or saline alone, guinea pigs and rats were exposed for 5 or 20 days, 6 hr/day, 5 days/week to filtered room air, 1 mg/m 3 ammonium sulfate (NH 4) 2SO 4) or 1 mg/m 3 ammonium nitrate (NH 4NO 3) aerosols. Pulmonary function evaluations conducted in guinea pigs showed no detrimental effects of (NH 4) 2SO 4 or NH 4NO 3 exposure and very little effect of elastase treatment. Lung function changes in elastase-treated rats were consistent with a condition of experimentally induced pulmonary emphysema. Rats exposed to NH 4NO 3 aerosols showed no consistent exposure-related changes. Compared with air-exposed animals, rats exposed to (NH 4) 2SO 4 aerosols had increased values of residual volume and functional residual capacity and decreased slope of single-breath N 2 washout curves. We conclude that elastase treatment had no significant effect on lung function changes resulting from inhalation of (NH 4) 2SO 4 aerosols. Lung function was more affected by (NH 4) 2SO 4 exposure than by NH 4NO 3 exposure, and lung function changes were more pronounced in rats than in guinea pigs.