Respiratory mucociliary clearance in the horse in health and disease, and its pharmaceutical modification.

The research article discusses the mucociliary clearance system in horses, both in health and disease conditions, as well as how various pharmaceuticals can modify it. The study mainly focuses on mucus production, its properties, and the important role of bronchodilator clenbuterol in improving mucociliary movement.

Respiratory Secretions in Equines

• The article begins by reviewing the structure and functions of respiratory secretions. For horses, the primary source of these secretions is goblet cells, which produce mucus.
• However, there is limited information about the volume or the composition of these equine respiratory secretions.
• The physical characteristics of airway mucus are complex and not fully understood yet, but they can be partially analyzed using various in vitro and biological techniques.

Mucus, Cilia and Lung Disease

• The relationship between mucus structure and its movement facilitated by airway cilia, both in health and disease, is deliberated.
• Mucokinesis, or the movement of mucus, has been visually assessed in horses by observing intratracheal markers during bronchoscopy and with the aid of radiographic and radioactive markers.
• Ongoing research indicates a tracheal mucous speed of around 20 mm/min in horses.

Mucokinetic Agents and their Effectiveness

• A variety of mucokinetic agents are analyzed that reportedly enhance mucokinesis through different mechanisms — from mucus thinners, surfactants, and mucolytics to bronchomucotropic agents, ciliary stimulants, and bronchodilators.
• A careful review of existing literature reveals that the bronchodilator clenbuterol is currently the most effective agent in enhancing mucokinesis in horses.

The study indicates a need for further research about equine respiratory secretions and the ways to enhance mucokinesis. Particularly, more knowledge about the physical characteristics of mucus and the role of various pharmaceuticals in modifying its structure and movement is deemed beneficial.