BACKGROUND Mild asthma in horses decreases racing performance and impairs gas exchange. The efficacy of treatment on performance is unknown. HYPOTHESIS Treatment targeting lung inflammation improves V ˙ O2 peak in horses with mild asthma. ANIMALS Thoroughbred polo horses (n = 12) with smoke-induced mild asthma. Horses were exposed to increased ambient particulate matter (35.51 μg/m3 [PM2.5 ]; day mean, centrally measured) from day -33 to 0, from bushfire smoke (natural model). METHODS Prospective, randomized, placebo-controlled, double-blinded clinical trial. All horses completed 3 V ˙ O2 peak tests, measuring aerobic and anaerobic variables: day 0 -baseline; day 16 -after dexamethasone (20 mg IM q24h; DEX, n = 6) or saline treatment (SALINE, n = 6), under improved ambient PM2.5 concentrations (7.04 μg/m3 ); day 17-15-30mins after inhaled salbutamol (1500 μg). Bronchoalveolar lavage and mucus scoring were performed on day -8 and day 20. Linear mixed effects models were used to examine the effects of timepoint and treatment group on BAL differential cell counts, mucus scores, aerobic and anaerobic variables. RESULTS Horses' mucus scores improved significantly from day -8 to 20 by 1.27 ± .38 (P = .01). There was a significant increase in V ˙ O2 peak of 15.5 ± 4.0 mL(min.kg)-1 from day 0 to 17 (P = .002), representing an average (mean) increase in V ˙ O2 peak of 13.2%. There was no difference in V˙O2 peak between treatment groups (SALINE versus DEX) at any timepoint. CONCLUSIONS AND CLINICAL IMPORTANCE This study highlighted the key role of improved air quality on functionally important airway inflammation. Evidence provided is central to increasing owner compliance regarding improved air quality for the treatment and prevention of mild asthma.

中文翻译：

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地塞米松，沙丁胺醇的功效以及可降低可吸入颗粒物浓度对烟雾诱发的轻度哮喘患者马匹有氧运动的能力。

背景技术马中的轻度哮喘降低了赛车性能并损害了气体交换。治疗对效果的功效尚不清楚。假设针对肺部炎症的治疗可改善患有轻度哮喘的马的V˙O2峰值。动物杂种马球（n = 12），有烟引起的轻度哮喘。在第-33天至0天之间，从丛林大火烟雾（自然模型）中，马暴露于增加的环境颗粒物（35.51μg/ m3 [PM2.5]；日平均值，中心测量）。方法前瞻性，随机，安慰剂对照，双盲临床试验。所有马匹完成3 V˙O2峰值测试，测量有氧和无氧变量：第0天-基线；地塞米松（20 mg IM q24h; DEX，n = 6）或盐水治疗（SALINE，n = 6）后第16天，在改善的环境PM2.5浓度（7.04μg/ m3）下; 吸入沙丁胺醇（1500μg）后第17-15-30分钟。在第-8天和第20天进行支气管肺泡灌洗和粘液评分。使用线性混合效应模型检查时间点和治疗组对BAL差异细胞计数，粘液评分，有氧和无氧变量的影响。结果马的黏液分数从第-8天到第20天明显改善了1.27±.38（P = .01）。从第0天到第17天，V˙O2峰值显着增加15.5±4.0 mL（min.kg）-1（P = .002），表示V˙O2峰值平均（平均值）增加13.2％。在任何时间点，治疗组（SALINE与DEX）之间的V˙O2峰值均无差异。结论和临床意义这项研究强调了改善空气质量对功能重要的气道炎症的关键作用。