摘要 : This study tested the hypothesis that phenylbutazone would block the exercise-induced increase in cytokine markers of inflammation in blood. Blood samples were obtained from unfit Standardbred mares (age 10+or-4 years, ~500 kg) be... 展开 This study tested the hypothesis that phenylbutazone would block the exercise-induced increase in cytokine markers of inflammation in blood. Blood samples were obtained from unfit Standardbred mares (age 10+or-4 years, ~500 kg) before and after three different trials (standing control (CON), <i>n</i>=9; exercise with phenylbutazone (EX-bute), <i>n</i>=9; and exercise with water, <i>n</i>=9). Comparisons were made for data collected in three trials, one where each horse underwent an incremental exercise test (graded exercise test (GXT)) where they were administered water as a placebo, a GXT following phenylbutazone administration (2 g given orally 2 h before the GXT) or standing parallel control where they stood quietly in stalls. During the GXT, horses ran on a treadmill (1 m s^-1 increases each min until fatigue, 6% grade). Blood samples were obtained 30 min before exercise, immediately after exercise and at 0.5, 1, 2, 4 and 24 h post-GXT or at matched time points during the parallel control trials. Samples were analysed using real-time PCR for measurement of mRNA expression of interferon- gamma (IFN- gamma ), tumour necrosis factor- alpha (TNF- alpha ) and interleukin (IL)-6 in samples collected during all three trials, and for IL-1 and IL-10 in samples collected for the CON and EX-bute trials. Data were analysed using ANOVA for repeated measures, and where appropriate, <i>post hoc</i> separation of means utilized the Student-Newman-Keuls test. The null hypothesis was rejected when <i>P</i><0.05. There were no changes (<i>P</i>>0.05) in IL-1, IL-6, IFN- gamma or TNF- alpha during CON or following phenylbutazone administration. During the water trial, exercise resulted in significant increases in IFN- gamma , IL-1 and TNF- alpha . It was concluded that high-intensity exercise results in a transient increase in the expression of inflammatory cytokines in blood that is blocked when phenylbutazone is administered to horses. 收起