Does training affect mRNA transciption for cytokine production in circulating leucocytes?

Area of Science:

• Equine immunology
• Exercise physiology
• Molecular biology

Background:

• Physical exertion is known to stimulate cytokine production in horses.
• Understanding these responses is crucial for managing equine health during training.

Purpose of the Study:

• To investigate the effects of a structured training program on leukocyte cytokine mRNA transcription in Thoroughbred horses.
• To determine if specific cytokines (IL-1beta, IL-1ra, IL-2, IL-4, IL-6, IL-10, TNF-alpha) are upregulated by exercise.

Main Methods:

• Five stall-rested Thoroughbreds underwent a progressive training regimen.
• Blood samples were collected weekly, and leukocyte mRNA levels were quantified using real-time TaqMan quantitative PCR.
• Statistical analysis included repeated measures ANOVA on ranks and Student-Newman-Keuls post-hoc tests.

Main Results:

• Interleukin-2 (IL-2), IL-4, IL-6, and IL-10 mRNA levels were unaffected by training or intense exercise.
• Interleukin-1 beta (IL-1beta) and Tumor Necrosis Factor-alpha (TNF-alpha) mRNA increased significantly by Day 23.
• Interleukin-1 receptor antagonist (IL-1ra) mRNA decreased initially, then increased significantly from Day 9 to Day 37.

Conclusions:

• Training alters specific cytokine mRNA expression in horses, with notable increases in IL-1beta and TNF-alpha.
• The dynamic changes in IL-1ra suggest a complex regulatory response to exercise.
• These cytokine modifications could influence susceptibility to infections, metabolic adaptations, or exercise-induced conditions in horses.