Identifying target genes involved in subclinical respiratory disease that develop in athletes: an insight from the horse athlete and the use of microarrays

The aim of the present study, using microarrays, was to find hitherto unknown target genes involved in the subclinical respiratory inflammation that are responsible for drop in exercise performance. It is hoped that this may improve understanding of the physiopathological pathways that are responsible for airway inflammation depending of the discipline involved and will likely have a clinical impact on sports medicine, and on the current approach to exercise-based rehabilitation in respiratory disease. Keywords: microarray, subclinical, airway, inflammation, sport, respiratory disease The study included 8 French Standardbred trotters, aged 2–8 years, 8 thoroughbred, aged 2-5 years, and 8 endurance horses, aged 7-12 years, referred to the Centre of Imaging and Research on Equine Locomotor Disease (CIRALE) between October 2006 and February 2008. To be included in the study, horses had to be either in competition at the time of the study or in active race training during the preceding 3 months. In each discipline, 4 fit and performing horses with no clinical disease and defined as healthy at the end of the tests were selected as controls and 4 horses not performing as expected and diagnosed as affected by inflammatory airway disease (IAD) following the criteria previously described (Robinson and Hoffman, 2003; Couëtil et al., 2007, Richard et al., 2009), were selected as inflammatory. Hybridisation on the Horse Gene Expression Microarray (Agilent) was performed in a single horse per chip and in a monocolore mode, using cyanine-3 (Cy3) labeling.