Abstract：
Horses maintained outdoors may experience a lower-allergenic environment compared to their stabled counterparts. This study hypothesizes that climatic changes in southern Brazil can influence respiratory status. To test this hypothesis, we evaluated the lower airways of 17 horses from a teaching herd in southern Brazil, maintained outdoors, during winter, spring, and summer. Except for one mare with a history of severe asthma, all horses were considered healthy and underwent a physical examination. Airway endoscopic evaluation included scoring for tracheal mucus (0-5) and bronchial septum thickness (1-5). Bronchoalveolar lavage fluid (BALF) was collected at three time points, while bronchial septum biopsies were performed during spring and summer for airway epithelial investigation. Data analysis involved repeated measures ANOVA and Wilcoxon tests (p < 0.05). Tracheal mucus score and septal thickness did not differ across investigation periods. In BALF cytology, the mean percentage of neutrophils was higher in spring than summer (7.9 ± 13.4 % vs. 4.5 ± 11.7 %, P = 0.037), and eosinophil count was higher in winter than spring (0.64 ± 1.29 % vs. 0.03 ± 0.13 %, P = 0.034) and summer (0.64 ± 1.29 % vs. 0.14 ± 0.60 %, P = 0.023). Histopathological observations showed no differences between time points, and no correlations were observed with BALF analyses (P > 0.05). This study demonstrates that, even in an outdoor environment, horses\' airways exhibit cytological modifications associated with different seasons, indicating a need for deeper investigation; endobronchial biopsy did not contribute to the clinical diagnosis.
摘要：
与稳定的马相比，在户外饲养的马可能会经历较低的致敏性环境。这项研究假设巴西南部的气候变化会影响呼吸状态。为了检验这个假设，我们评估了巴西南部一个教学群的17匹马的下呼吸道，保持在户外，在冬天,spring,和夏天。除了一匹有严重哮喘病史的母马,所有马被认为是健康的,并接受了体格检查.气道内镜评估包括气管粘液评分（0-5）和支气管隔膜厚度评分（1-5）。在三个时间点收集支气管肺泡灌洗液（BALF），在春季和夏季进行支气管间隔活检以进行气道上皮检查。数据分析涉及重复测量ANOVA和Wilcoxon检验(p<0.05)。在调查期间，气管粘液评分和间隔厚度没有差异。在BALF细胞学中，春季中性粒细胞的平均百分比高于夏季（7.9±13.4％vs.4.5±11.7%，P=0.037),嗜酸性粒细胞计数在冬季高于春季（0.64±1.29%vs.0.03±0.13%,P=0.034）和夏季（0.64±1.29%vs.0.14±0.60%，P=0.023)。组织病理学观察显示时间点之间没有差异，与BALF分析无相关性(P>0.05)。这项研究表明,即使在户外环境中，马的呼吸道表现出与不同季节相关的细胞学变化，表明需要进行更深入的检查；支气管内活检对临床诊断没有帮助。
