Comparison of TGF-beta 1 concentrations in bronchoalveolar fluid of horses affected with heaves and of normal controls

Airway remodeling may play an important role in heaves pathophysiology. Transforming growth factor-beta 1 (TGF-β1) is a potent profibrotic cytokine, which might contribute to airway wall thickening and fibrosis of bronchiolar and alveolar submucosa. SA designed for the measurement of human TGF-β1 was used to measured total TGF-β1 released in bronchoalveolar lavage fluid (BALF) of normal horses and of those affected with heaves in remission. The specificity of the assay for TGF-β1 of the horse was confirmed using recombinant equine TGF-β1. The influence of hay exposure on TGF-β1 release in the airways was also examined by stabling horses in a dusty environment. TGF-β1 was found in the BALF of all horses. However, no significant difference between basal concentration of TGF-β1 in BALF of control horses versus that of horses affected with heaves was found. Furthermore, no differences were identified in these populations 1 and 9 days after allergen challenge. clusion, these data indicate that TGF-β1 is released in BALF fluid of horses in biologically active concentrations. Other studies are necessary for a better definition of the role of this cytokine within the lung, as our study does not establish a causal relationship between TGF-β1 and the pathophysiology of heaves in the horse.