Department of Veterinary Medicine, Federal University of Viçosa, Viçosa, Minas Gerais, Brazil.
Department of Veterinary Medicine, Federal University of Viçosa, Viçosa, Minas Gerais, Brazil.
Res Vet Sci. 2021 May;136:550-560. doi: 10.1016/j.rvsc.2021.04.013. Epub 2021 Apr 15.
Amblyomma sculptum is frequently observed parasitizing horses, responsible for economic losses, damage to the host''s skin and transmission of pathogens. The oxidative stress profile and inflammatory mechanisms involved in this parasitism remain poorly studied. Thus, this study aimed to assess the histopathological changes and oxidative profile responses of horses in the attachment site of A. sculptum to find variations that indicate resistance and susceptibility between the breeds to this tick, based on the hypothesis that resistant animals have a greater inflammatory response and lesser number of attached ticks. We analyzed female horses of two breeds, Mangalarga Marchador and Breton Postier, naturally infested by Amblyomma sculptum. The ticks were counted and full-thickness excisional skin wounds of 10 mm were made on the perineal region on the attachment site of partially engorged females for histological and biochemical analyzes. The occurrence of the tick on the skin caused an increase in cellularity, inflammatory infiltrate, mast cells, pyknotic nuclei, and changes in the fibrous components of the matrix. The negative correlation observed between tick infestation and inflammatory response indicated that animals with greater inflammatory response tend to have less tick infestation. The oxidative stress markers, MDA, PCN and NO not present great variation; however, between the antioxidant enzymes levels, SOD was higher in tick attachment of Breton Postier skin, this may mean that these animals had higher oxidative enzymatic activity and consequently less tissue damage, while the GST dropped in the attachment sites compared to the control, which may indicate that animals were in a state of significant oxidative stress or raises the question of the possibility of enzymatic sequestration by ticks. No significant differences were found in the resistance of the two breeds since most of the analyzes varied due to the presence or absence of the tick attached to the skin. We draw attention to the importance of studying characteristics of the animal's antioxidant responses to the tick and the action of tick saliva on antioxidant enzymes and ROS because these characteristics are interdependent with the inflammatory response.
纹皮扇头蜱常寄生在马体上，造成经济损失、宿主皮肤损伤和病原体传播。然而，这种寄生关系中的氧化应激谱和炎症机制仍研究甚少。因此，本研究旨在评估马匹在纹皮扇头蜱附着部位的组织病理学变化和氧化谱反应，寻找表明对这种蜱的抗性和敏感性的变化，基于以下假设：抗性动物具有更强的炎症反应和更少的附着蜱。我们分析了两种马的雌性，马加拉加三月马和布雷顿波斯特马，它们自然感染了纹皮扇头蜱。对附着在部分饱血雌性身上的 10mm 全层切除皮肤伤口进行计数和皮肤组织学及生物化学分析。蜱在皮肤上的出现导致细胞增多、炎症浸润、肥大细胞、固缩核和基质纤维成分的变化。观察到的蜱的感染与炎症反应之间的负相关表明，具有更强炎症反应的动物往往具有较少的蜱感染。氧化应激标志物 MDA、PCN 和 NO 没有很大的变化；然而，在抗氧化酶水平之间，布雷顿波斯特马皮肤的 SOD 在蜱附着处较高，这可能意味着这些动物具有更高的氧化酶活性，因此组织损伤较少，而 GST 在附着部位下降与对照相比，这可能表明动物处于严重的氧化应激状态，或者提出了蜱可能对酶进行隔离的可能性。由于附着在皮肤上的蜱的存在或不存在，两种品种的抗性没有明显差异，大多数分析都有所不同。我们提请注意研究动物抗氧化反应对蜱和蜱唾液对抗氧化酶和 ROS 的作用的特征的重要性，因为这些特征与炎症反应相互依存。
