The Effect of Race Training on the Basal Gene Expression of Alveolar Macrophages Derived From Standardbred Racehorses.

This research investigates how race training affects the gene expression of alveolar macrophages, immune cells found in the lungs, in Standardbred racehorses, potentially providing insight into why these horses may be more susceptible to asthma.

Study Overview

• Researchers conducted a genome-wide scan of base gene expressions in alveolar macrophages, cells in the lungs that are part of the immune system. They did this both before and after the racehorses began their competition training.
• The macrophages were obtained from the bronchoalveolar fluid of six healthy Standardbred racehorses.
• The goal was to identify changes in gene expression that may indicate changes in immune function related to the training.

Method and Tools

• The scientists used microarray technology to analyze the gene expression in the alveolar macrophages from the horses’ lungs.
• They also measured the release of TNF-α and IL-10, two cytokines or signaling molecules of the immune system, in response to lipopolysaccharide, an inflammatory stimulus, at both time points (before and after training).

Findings

• Significant variation was observed between the horses regarding the amount of individual gene expression at each timepoint. Nonetheless, within each individual horse, several genes associated with inflammation—such as chemokine ligands, interferons, and the nuclear factor kappa-light-chain-enhancer of activated B cells (NFKB)—showed decreased expression from T0 (before training) to T1 (after training).
• The amount of cytokines produced in response to lipopolysaccharide did not change significantly with the onset of training.

Significance and Implications

• These findings suggest that race training directly impacts the gene expression of lung macrophages, particularly genes related to the immune system.
• The observed gene expression patterns suggest a possible immunosuppressive effect of training, marked by a downregulation of genes associated with inflammation.
• This could potentially increase the horse’s vulnerability to various pathogens, offering a possible explanation for the increased incidence of mild to moderate asthma in young racehorses.