Abnormalities in lung surfactant in horses clinically affected with recurrent airway obstruction (RAO).

This research investigates the differences in lung surfactant in healthy horses and those struggling with recurrent airway obstruction (RAO), a disease similar to asthma in humans. The study found abnormal surfactant characteristics in RAO-affected horses, suggesting a potential factor contributing to RAO’s pathophysiology.

Methodology

• The study included 6 healthy horses and 5 horses with RAO. From these horses, Bronchoalveolar lavage fluid (BALF) was obtained using standard procedures.
• The collected BALF was stripped of cells, leaving behind crude surfactant pellets (CSP) and supernatant, separated via ultracentrifugation. These were then analyzed for phospholipid and protein content.
• The phospholipid composition of CSP was identified using high-performance liquid chromatography, a technique that separates mixes into their component parts, coupled with an evaporative light scatter detector.
• The surface tension of CSP, which relates to the functioning of the surfactant, was measured using a pulsating bubble surfactometer.

Results

• In comparing RAO-affected horses with healthy ones, it was found that surfactant from RAO-affected horses had significantly decreased phospholipid content in both total surfactant and CSP.
• Moreover, the percentage of phosphatidylglycerol (PG), a crucial component of pulmonary surfactant, was also significantly lower in RAO-affected horses.
• The ratio between the percentages of another major surfactant component, phosphatidylcholine, and PG was significantly higher in RAO-affected horses than in healthy ones.

Conclusions

• The study concludes that the surfactant in RAO-affected horses is indeed abnormal when compared with that in healthy horses.
• However, the research also calls for further studies to determine if these abnormalities contribute to an increased inclination for bronchoconstriction and a decreased capacity to clear airway mucus in RAO-affected horses.