Training-associated alterations in equine respiratory immunity using RNAseq

Neutrophilic airway inflammation is highly prevalent in racehorses in training, with the term mild to moderate equine asthma (MMEA) being applied to the majority of such cases. The current study is largely derived from the strong association between MMEA in racehorses and their entry into a race training program; this has led to our primary aim of measuring the effect of race training on pulmonary immune cell function. The objectives of this study are to characterise the effect of training on the local pulmonary immune system and quantify the magnitude of effect by defining the gene expression of tracheal wash (TW) derived cells from Thoroughbred racehorses prior to (T0) and following commencement of race training (T1). This study demonstrated TW samples to represent a rich source of airway cells and RNA to study airway immunity in the horse and highlighted the benefits of advanced-omic methodological approach to studying the dynamics of equine airway immunity. Intense training induced quantifiable alterations in both gene expression of airway derived cells consistent with deregulation of airway immunity and haemopoietic abnormalities. Respectively, these findings likely reflect the known associations between race training and both airway inflammation and bleeding, in particular offering further insight into the potential mechanisms which underpin training associated airway inflammation. Tracheal wash (TW) samples were obtained at both time points (T0, T1) from the same Thoroughbred horses (n=16). Gene expression of TW derived cells was determined by RNAseq and analysed by DEseq2