Effect of stabling on bronchoalveolar cells obtained from normal and COPD horses

Abstract

Summary Bronchoalveolar lavages (BAL) were performed before and after 3 weeks of housing in 5 horses suffering from COPD and 5 normal horses. In the two groups, the total number of cells recovered remained unchanged after stabling. The most common cell populations in BAL fluid of control animals were alveolar macrophages (46.4%) and lymphocytes (44.9%). The percentage of neutrophils increased after stabling from 8.7% to 27.6%. In COPD horses, lymphocytes predominated (40.7%) in animals at pasture with neutrophils increasing from 29.4% to 71.6% after stabling. After fractionation by Percoll density gradient, alveolar macrophages and neutrophils from normal and COPD horses had a similar density distribution. After stabling, these cells from normal horses were increased in the low density layers, while those from COPD horses were predominantly in the hyperdense layers. Therefore, BAL cells obtained from COPD animals at pasture and after stabling differ from those of control horses in the same environment, not only in their populations but also in their buoyant densities. These differences could be related to different states of cellular activation and perhaps be responsible for disease activity in the COPD horses.

Association between Respiratory Disease and Bacterial and Viral Infections in British Racehorses

“…A previous study found that the mean duration of IAD incidents was significantly higher for horses kept in an environment where dust loading was higher and ventilation was less well regulated (10). Respirable endotoxin, measured at the level of horses' nares, has been shown to be correlated with levels of neutrophilic inflammation in similar racehorses in Australia (31), and stabling in itself can cause some inflammation in airways (27,50). However, direct comparison of these factors was outside the objectives of this work.…”

“…Studies focusing on individual agents suggest the possible involvement of viral infection (59), bacterial infection (10,14,16,42,43,56), and environmental loading of the respiratory system (10,27,33,50), as well as dysregulation of inflammatory processes (6). Individual bacteria commonly reported from cases include Streptococcus zooepidemicus (10,14,16,42,56), Streptococcus pneumoniae (14,16,56), Actinobacillus spp.…”

Lung inflammatory responses

“…Interestingly, despite years of previous antigenic stimulation, there was no polarization of lymphocytes to a T H 2-type of response in horses with COPD during clinical remission [40]. Typically, neutrophils are recruited to the lungs of horses with COPD and further add to the inflammatory process [24,57,128]. There is evidence that T H 2 cytokines are involved in the modulation of the inflammation from a neutrophilic to an eosinophil-induced type of inflammation [24,57].…”

Air Quality in Horse Stables

“…There are also various analyses aimed to examine cellular and non-cellular immunologic components. Diagnosis of airway inflammation in horses is determined based on a combination of history, clinical examination, endoscopy and, in many instances, bronchoalveolar lavage (BAL) cytology (Derksen et al, 1985;Tremblay et al, 1993). Results from pulmonary function tests are used in research and for clinical purposes for disease monitoring and in grading of disease severity (Derksen et al, 1985).…”