Background

Immunological mechanisms involved in the pathogenesis of mild to moderate equine asthma (MEA) are not completely understood. There are limited data on bronchoalveolar lavage fluid (BALF) and blood inflammatory cytokine profiles in racehorses with MEA, and the effect of racing on inflammatory cytokines is unknown.

Hypothesis/objectives

We hypothesized that inflammatory cytokine gene expression in BALF and resting blood would be higher in racehorses with lower airway inflammation compared to healthy controls, and that gene expression in blood collected immediately post-race would be increased compared to resting blood in racehorses with lower airway inflammation.

Animals

38 racing Thoroughbreds (samples: 30 resting blood, 22 post-race BALF, 41 post-race blood).

Methods

Prospective observational study. Inflammatory cytokine gene expression was determined in resting blood, post-race BALF and post-race blood from racehorses with lower airway inflammation and controls.

Results

Lower airway inflammation was diagnosed in 79 % of racehorses (23 % neutrophilic, 67 % mastocytic, and 10 % mixed). There was no difference in gene expression in BALF or resting blood between racehorses with lower airway inflammation and controls. IL-8 gene expression was higher in post-race blood compared to resting peripheral blood, regardless of disease (p = 0052). BALF neutrophil proportions increased with increasing IL-1β gene expression in all sample types (p = 0.0025). BALF mast cell proportions increased with increasing TNF-α gene expression in post-race blood (p = 0.015).

Conclusions and clinical importance

Lower airway inflammation was common in a population of racehorses without respiratory signs or exercise intolerance. Exercise alone increased peripheral blood IL-8 gene expression. Inflammatory cytokine gene expression was not increased in BALF or resting blood in horses with subclinical lower airway inflammation, precluding its diagnostic utility in clinical practice.

中文翻译：

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下呼吸道炎症对赛跑纯种马支气管肺泡灌洗液和全血炎性细胞因子基因表达的影响

背景

涉及轻度至中度马哮喘 (MEA) 发病机制的免疫学机制尚不完全清楚。关于患有 MEA 的赛马的支气管肺泡灌洗液 (BALF) 和血液炎症细胞因子谱的数据有限，并且赛马对炎症细胞因子的影响尚不清楚。

假设/目标

我们假设与健康对照相比，BALF 和静息血中的炎性细胞因子基因表达在气道炎症较低的赛马中会更高，并且与气道炎症较低的赛马的静息血相比，赛马后立即收集的血液中的基因表达会增加.

动物

38 匹赛马纯种马（样本：30 匹静止血，22 匹赛后 BALF，41 匹赛后血液）。

方法

前瞻性观察研究。在静息血、赛后 BALF 和来自具有下呼吸道炎症的赛马和对照的赛马血液中测定了炎症细胞因子基因表达。

结果

79% 的赛马（23% 中性粒细胞、67% 肥大细胞和 10% 混合）被诊断出下呼吸道炎症。下呼吸道炎症的赛马和对照组之间的 BALF 或静息血液中的基因表达没有差异。与静息外周血相比，赛后血液中的 IL-8 基因表达更高，无论疾病如何（p = 0052）。BALF 中性粒细胞比例随着所有样本类型中 IL-1β 基因表达的增加而增加（p = 0.0025）。BALF 肥大细胞比例随着赛后血液中 TNF-α 基因表达的增加而增加（p = 0.015）。

结论和临床重要性

下呼吸道炎症在没有呼吸道症状或运动不耐受的赛马群体中很常见。单独运动会增加外周血IL-8基因的表达。炎症性细胞因子基因表达在 BALF 或亚临床下呼吸道炎症马的静息血中没有增加，排除了其在临床实践中的诊断效用。