[Elastase-induced hyperfunction of submucous glands develops independent of elastase-induced emphysema]

We instilled 2 mg of pancreatic elastase into the lungs, and insufflated a further 2 mg into the trachea of 6 male ferrets. Six control animals were given 0.9% NaCl (lungs) and glucose powder (trachea). This combined treatment was administered on days 1, 8 and 15. On these days, and again on days 29 and 39, we obtained chest x-rays. On the 39th day, we removed the lungs and measured the mean linear intercept. In tracheal sections, we measured goblet cell density, glandular structure and function by quantitative histology and autoradiography. Although, up to day 39, no emphysema developed, both structural and functional changes occurred in the glands: the volume density of the serous glands (S) decreased, that of the mucous glands (M) increased, the ratio S/M decreased from 2.0 to 1.5 (p = 0.05). The turnover of radioactive sulphur (indication of mucus synthesis) was significantly increased in animals treated with elastase (p = 0.001). Goblet cells increased from 0.9 +/- 0.4 to 3.4 +/- 1.8 cells per mm epithelium (p = 0.05). The results show that elastase induces structural and functional changes in submucosal glands and goblet cell hyperplasia, independently of emphysema.