Equine Sports Medicine Laboratory "Franco Tradati", Department of Veterinary Medicine and Animal Sciences, Università degli Studi di Milano, Via dell'Università 6, Lodi 26900, Italy.
Department of Veterinary Medicine, Università degli Studi di Sassari, Via Vienna 2, Sassari 07100, Italy.
J Equine Vet Sci. 2024 Apr;135:105033. doi: 10.1016/j.jevs.2024.105033. Epub 2024 Feb 27.
Equine asthma (EA) is a respiratory syndrome associated with the increase of different leukocyte populations in the bronchoalveolar lavage fluid (BALF). Its pathogenetic mechanisms remain unclear. This study aimed to evaluate the associations between the mRNA expression of different cytokines in the BALF, different EA subtypes and lung function. Fifteen horses underwent physical examination, airway endoscopy, BALF cytology and lung function testing (8/15). One horse did not have evidence of EA and was used as healthy reference, while the others were classified as affected by neutrophilic or mixed granulocytic EA. Cells isolated from the residual BALF were used for IL-1β, IL-2, IFN-γ, IL-4, IL-17A genes expression by quantitative RT-PCR., Cytokine expression was compared between groups, and their correlations with BALF leukocyte and lung function were evaluated. IL-1β expression was positively correlated with BALF neutrophils count (p=0.038, r=0.56) and with increased expiratory resistance (p=0.047, r=0.76). IFN-γ was correlated with BALF mast cells (p=0.029, r=0.58). IL-4 was higher in horses with mixed granulocytic EA than neutrophilic (p=0.008), positively correlated with BALF mast cells (p=0.028, r=0.59) and inversely with whole-breath (p=0.046, r=-0.76) and expiratory reactance (p=0.003, r=-0.93). Finally, IL-17A was inversely correlated with expiratory reactance (p=0.009, r=-0.92). These results support that multiple immune responses are involved in EA pathogenesis; innate, Th2, and Th17 responses. Innate immunity appeared associated with neutrophilic inflammation, and Th2 response with increased mast cells. The role of Th1 response in EA remains questionable.
马气喘病（EA）是一种与支气管肺泡灌洗液（BALF）中不同白细胞群增加相关的呼吸系统综合征。其发病机制尚不清楚。本研究旨在评估 BALF 中不同细胞因子的 mRNA 表达与不同 EA 亚型和肺功能之间的关系。15 匹马接受了体格检查、气道内窥镜检查、BALF 细胞学和肺功能测试（8/15）。一匹马没有 EA 的证据，被用作健康参考，而其他马则被归类为中性粒细胞或混合粒细胞性 EA。从剩余的 BALF 中分离出的细胞通过定量 RT-PCR 用于 IL-1β、IL-2、IFN-γ、IL-4、IL-17A 基因表达。比较各组之间的细胞因子表达，并评估其与 BALF 白细胞和肺功能的相关性。IL-1β 表达与 BALF 中性粒细胞计数呈正相关（p=0.038，r=0.56），与呼气阻力增加呈正相关（p=0.047，r=0.76）。IFN-γ 与 BALF 肥大细胞相关（p=0.029，r=0.58）。混合粒细胞性 EA 马的 IL-4 高于中性粒细胞性 EA（p=0.008），与 BALF 肥大细胞呈正相关（p=0.028，r=0.59），与全呼（p=0.046，r=-0.76）和呼气电抗（p=0.003，r=-0.93）呈负相关。最后，IL-17A 与呼气电抗呈负相关（p=0.009，r=-0.92）。这些结果支持多种免疫反应参与 EA 的发病机制；先天、Th2 和 Th17 反应。先天免疫似乎与中性粒细胞炎症有关，而 Th2 反应与肥大细胞增加有关。Th1 反应在 EA 中的作用仍存在疑问。
