Hyperosmolar Solutions Stimulate Mucus Secretion in the Ferret Trachea
Sputum induction using hypertonic saline solution inhalation has been used to obtain sputum specimens for diagnosing airway infection and for collecting secretions for research. More than 20 years ago, it was shown that when patients with chronic bronchitis inhaled a 7% (7 g/dL, 2,396 mOsm/L) saline aerosol, whole-lung mucociliary clearance (MCC) increased by 100% in the first 90 min over the clearance rate after inhalation of isotonic (0.9%) saline solution. More recently, patients with cystic fibrosis CF) were randomly assigned to receive either 0.9% saline or 6% saline by ultrasonic nebulization. Spirometry was measured before initiating the study, at day 14 after 2 weeks of study drug, and at day 28, 2 weeks after therapy was discontinued. Among the patients who completed these studies, there was a significant increase in FEV1 in those inhaling hypertonic saline solution, and this returned to baseline by day 28. my canadian pharmacy online
The mechanism by which hyperosmolar agents increase MCC has not been established. The increase in MCC could be due to an increase in airway secretion volume, an increase in ciliary activity, or a change in the properties of the secretions.- We hypothesized that hyperosmolar solutions would increase mucin (mucous cell) and lysozyme (serous cell) secretion in the ferret trachea in a dose-dependent manner.
Materials and Methods
Airway mucus is composed of secretory products produced from different cell populations. In the larger airways of many mammals, including man, the submucosal glands and epithelial goblet cells are the major sources of mucus. The ferret trachea is a robust model to study airway mucus secretion because of its long length and high glandularity similar to the human airway and unlike other small animals. We have studied the regulation of mucous and serous cell secretion under a variety of experimental conditions using the ferret tracheal model.