Abstract：
Laminitis is a pathology of the equine digit ultimately leading to a failure of the dermo-epidermal interface. Neutrophil activation is recognized as a major factor in SIRS-associated laminitis and has recently been described in induced endocrinopathic laminitis evidenced by the presence of myeloperoxidase (MPO). Neutrophil extracellular traps (NET) are released with neutrophil activation. This study aimed to investigate the presence and activity of MPO and NET in the lamellar tissue of equids presented with naturally occurring laminitis. Samples of lamellar tissue of five horses and five donkeys presented with laminitis, as well as eight control horses without laminitis, were collected. Lamellar tissue extracts were submitted to ELISA and specific immuno-extraction followed by enzymatic detection (SIEFED) assays to confirm the presence and activity of both MPO and NET. Lamellar sections were also immunohistopathologically stained for MPO and NET. Analysis of lamellar tissue extracts revealed that laminitis cases had significantly higher levels of total MPO concentration, MPO activity, and NET-bound MPO activity in comparison to control horses. Moreover, a strong correlation was identified between the activity of NET-bound MPO and the total MPO activity, which suggests that MPO activity partly originates from NET-bound MPO. Immunohistochemical staining showed that MPO and NET labelling in laminitis cases was moderate to marked, primarily in the epidermis and in inflammatory infiltrates containing neutrophils, while labelling in control horses was minimal. This article constitutes the first indication of the presence and activity of NET-bound MPO in the lamellar tissue of horses and donkeys with naturally occurring laminitis. Targeting these substances may provide new treatment possibilities for this debilitating disease.
摘要：
椎板炎是马指的病理，最终导致皮肤-表皮界面的失败。中性粒细胞活化被认为是SIRS相关椎板炎的主要因素，最近在由髓过氧化物酶（MPO）的存在证明的诱发性内分泌病性椎板炎中被描述。中性粒细胞胞外诱捕网(NET)随中性粒细胞活化而释放。这项研究旨在研究MPO和NET在自然发生的板层组织中的存在和活性。五匹马和五只驴的层状组织样本表现为椎板炎，以及八匹没有椎板炎的对照马，被收集。将板层组织提取物进行ELISA和特异性免疫提取，然后进行酶检测（SIEFED）测定，以确认MPO和NET的存在和活性。还对薄层切片进行MPO和NET的免疫组织病理学染色。板层组织提取物的分析表明，椎板炎病例的总MPO浓度水平明显较高，MPO活动,与对照马相比，与NET结合的MPO活性。此外，净结合MPO的活性与总MPO活性之间存在很强的相关性，这表明MPO活动部分源于NET绑定的MPO。免疫组织化学染色显示，椎板炎病例的MPO和NET标记为中度至明显，主要在表皮和含有中性粒细胞的炎症浸润中，而对照马匹的标签很少。本文首次表明了与NET结合的MPO在具有自然发生的椎板炎的马和驴的板层组织中的存在和活性。靶向这些物质可能为这种使人衰弱的疾病提供新的治疗可能性。
