Alimentary carbohydrate overload induces systemic inflammation in horses.
Introduction
Clinical signs of systemic inflammation have been detected after carbohydrate overload, but inflammatory cytokine responses have not been characterized.
Materials & Methods
Blood was obtained from 14 adult horses that received 10g/kg body weight oligofructose (OF) to induce laminitis at another institution. Total RNA was extracted from whole blood samples collected at 0, 8, 12, 16, 20, and 24 hours. Real-time PCR analysis was performed to detect mRNA expression of the target cytokines IL-1β, IL-6, IL-8, IL-10, TNFα, and the housekeeping gene β-glucuronidase (β-Gus). The comparative CT (ΔΔCT) method was used to calculate relative mRNA expression. Mixed model analysis of variance for repeated measures was performed on log10 transformed data. Back-transformed least squares means ± SEM are reported.
Results
All animals developed clinically detectable laminitis within 24 hours. Interleukin-1β, IL-6, IL-8, and IL-10 mRNA expression in blood significantly increased (P < 0.010) over time. Interleukin-1β expression peaked at 16 hours (8.1 ± 1.4-fold increase), IL-8 expression showed peaks at 8 (13.0 ± 4.1 fold increase) and 20 hours (20.8 ± 5.5 fold increase), IL-10 expression peaked at 16 hours (7.3 ± 1.7-fold increase), and IL-6 expression peaked at 16 hours (7.5 ± 3.3-fold increase). No significant change in TNFα mRNA expression was detected.
Discussion
Systemic inflammation develops in response to alimentary carbohydrate overload and this problem may occur when horses are grazing on pasture.
Clinical Relevance
Alimentary carbohydrate overload is an inflammatory event and should be treated accordingly.
Conclusion
Systemic inflammation may be an important component of pasture-associated laminitis in equids.
1Department of Large Animal Clinical Sciences, University of Tennessee, Knoxville, TN
2Department of Veterinary Science, Maxwell Gluck Equine Research Center, University of Kentucky, Lexington, KY
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