Age-related dynamics of pro-inflammatory cytokines in equine bronchoalveolar lavage (BAL) fluid and peripheral blood from horses managed on pasture.

The research examines the variation of pro-inflammatory cytokines in the peripheral blood and lower airways of horses as they age, and finds that continued low antigen exposure may regulate mRNA gene expression and favor an age-related accumulation of mRNA genes.

Objective of the Research

• The study aimed to examine the natural age-related changes and compare the level of pro-inflammatory cytokines in the peripheral blood and lower airways of horses. The research focused on the mRNA expression of several cytokines in bronchoalveolar lavage (BAL) fluid and peripheral blood mononuclear cells (PBMC).

Methodology

• The research team studied 44 horses of varying ages, analyzing their BAL fluid and PBMC for mRNA expression of the cytokines IL-1β, IL-6, IL-8 TNF-α and TLR-4, using quantitative real-time PCR and differential cell count cytology.

Key Findings

• The results showed a significant increase with age in the mRNA expression of IL-6, IL-8, TLR-4, and TNF-α in stimulated BAL cells, and for TNF-α in stimulated PBMC. Also, they observed a significant decrease in the mRNA expression of IL-1β and TNF-α in stimulated BAL cells compared to stimulated PBMC.

Conclusion

• From the results, the study concluded that continued low exposure to antigens from pasturing could have a regulatory effect on mRNA gene expression in the airway space as opposed to peripheral blood. This process, in turn, may favor an age-related accumulation of mRNA genes in horses.