Department of Animal Medicine and Surgery, Faculty of Veterinary Sciences, University of Cordoba, Córdoba, Spain.
Faculty of Veterinary Sciences, University of Cordoba, Francisco Santisteban Hospital, Campus de Rabanales, 14014, Córdoba, Spain.
BMC Vet Res. 2020 Feb 12;16(1):54. doi: 10.1186/s12917-020-02279-6.
Intestinal ischemia-reperfusion (IR) is an important clinical occurrence seen in common diseases, such as gastric dilatation-volvulus in dogs or colic in horses. Limited data is available on the use of methylene blue in veterinary medicine for intestinal ischemia-reperfusion. The present study aimed to compare the hemodynamic, histopathological, and immunohistochemical effects of two doses of methylene blue in two rabbit model groups In one group, 5 mg/kg IV was administered, and in another, 20 mg/kg IV was administered following a constant rate infusion (CRI) of 2 mg/kg/h that lasted 6 h. All the groups, including a control group had intestinal ischemia-reperfusion. Immunohistochemical analysis was performed using caspase-3.
During ischemia, hemodynamic depression with reduced perfusion and elevated lactate were observed. During reperfusion, methylene blue (MB) infusion generated an increase in cardiac output due to a positive chronotropic effect, an elevation of preload, and an intense positive inotropic effect. The changes in heart rate and blood pressure were significantly greater in the group in which methylene blue 5 mg/kg IV was administered (MB5) than in the group in which methylene blue 20 mg/kg IV dose was administered (MB20). In addition, lactate and stroke volume variations were significantly reduced, and vascular resistance was significantly elevated in the MB5 group compared with the control group and MB20 group. The MB5 group showed a significant decrease in the intensity of histopathological lesion scores in the intestines and a decrease in caspase-3 areas, in comparison with other groups.
MB infusion produced improvements in hemodynamic parameters in rabbits subjected to intestinal IR, with increased cardiac output and blood pressure. An MB dosage of 5 mg/kg IV administered at a CRI of 2 mg/kg/h exhibited the most protective effect against histopathological damage caused by intestinal ischemia-reperfusion. Further studies with MB in clinical veterinary pathologies are recommended to fully evaluate these findings.
肠缺血再灌注（IR）是一种常见疾病中的重要临床事件，例如犬的胃扩张-扭转或马的疝痛。兽医中关于亚甲蓝在肠缺血再灌注中的应用的数据有限。本研究旨在比较两种剂量的亚甲蓝在两种兔模型组中的血流动力学、组织病理学和免疫组织化学效应。在一组中，静脉内给予 5mg/kg，在另一组中，静脉内给予 20mg/kg，同时持续 6 小时以 2mg/kg/h 的速率输注。所有组，包括对照组，都经历了肠缺血再灌注。使用半胱天冬酶-3 进行免疫组织化学分析。
在缺血期间，观察到灌注减少和乳酸升高导致的血液动力学抑制。在再灌注期间，亚甲蓝（MB）输注由于正变时作用、前负荷升高和强烈的正变力作用而导致心输出量增加。静脉内给予 5mg/kg 亚甲蓝（MB5）的组中，心率和血压的变化明显大于静脉内给予 20mg/kg 亚甲蓝（MB20）的组。此外，与对照组和 MB20 组相比，MB5 组的乳酸和每搏量变化显著降低，血管阻力显著升高。与其他组相比，MB5 组的肠道组织病理学病变评分强度显著降低，半胱天冬酶-3 面积减少。
MB 输注可改善兔肠 IR 后的血流动力学参数，增加心输出量和血压。以 2mg/kg/h 的 CRI 静脉内给予 5mg/kg 的 MB 表现出对肠缺血再灌注引起的组织病理学损伤的最有效保护作用。建议在临床兽医病理学中进一步研究 MB，以充分评估这些发现。
