Abstract:
Selecting a method of euthanasia is an important step in designing research studies that use animals; euthanasia methods must be humane, cause minimal pain and suffering to the animal, and preserve the tissue architecture of the organs of interest. In this study, we evaluated the histomorphology of the internal organs (lung, spleen, heart, kidney, liver, brain, and adrenal gland) of rats submitted to five different methods of euthanasia, with the goal of determining which protocol caused the least alteration of histomorphology. Twenty adult Wistar Han rats (Rattus norvegicus) were divided into 5 groups of 4 rats each (2 females and 2 males) and were euthanized by CO₂ or isoflurane inhalation, sodium thiopental or xylazine plus ketamine overdose, or decapitation. All euthanasia was performed in accordance with published guidelines and local legal require- ments. Necropsy was performed immediately after euthanasia. Specific internal organs were removed and placed in formalin and submitted for routine histologic processing. Histomorphological examination of hematoxylin and eosin-stained tissues revealed circulatory alterations in multiple organs, predominantly congestion in multiple tissues, pulmonary hemorrhage, and hepatic degeneration. The euthanasia methods that induced the most severe alterations were exposure to CO₂ and anesthetic overdose with xylazine plus ketamine or sodium thiopental. Euthanasia by overexposure to isoflurane caused less damage, and the alterations were of minimal severity. Decapitation resulted in the lowest incidence of lesions in multiple organs but due its traumatic nature, it caused the highest incidence of pulmonary hemorrhage. In selecting a method of euthanasia, factors to consider are the species of animal, the purpose of the research, and the practical ability to perform the procedure to achieve maximal animal welfare without iatrogenic changes that could compromise the outcome and reproducibility of the study.
摘要:
选择安乐死的方法是设计使用动物的研究研究的重要步骤;安乐死的方法必须是人道的,对动物造成最小的痛苦和痛苦,并保留感兴趣器官的组织结构。在这项研究中,我们评估了内脏器官的组织形态学(肺,脾,脾心,肾,肝脏,大脑,和肾上腺)接受五种不同安乐死方法的大鼠,目的是确定哪种方案引起的组织形态学改变最小。将20只成年Wistar汉族大鼠(Rattusnorvegicus)分为5组,每组4只大鼠(2只雌性和2只雄性),并通过CO2或异氟烷吸入安乐死,硫喷妥钠或赛拉嗪加氯胺酮过量,或者斩首。所有安乐死都是根据公布的指南和当地法律要求进行的。安乐死后立即进行尸检。将特定的内部器官取出并置于福尔马林中,并进行常规组织学处理。苏木精和曙红染色组织的组织形态学检查显示多个器官的循环改变,主要在多个组织充血,肺出血,和肝变性。引起最严重变化的安乐死方法是暴露于CO2和过量使用赛拉嗪加氯胺酮或硫喷妥钠的麻醉剂。过度暴露于异氟烷的安乐死造成的损害较小,并且改变的严重程度最小。斩首导致多个器官的病变发生率最低,但由于其创伤性,它引起肺出血的发病率最高。在选择安乐死的方法时,要考虑的因素是动物的种类,研究的目的,以及执行该程序以实现最大动物福利的实际能力,而不会发生可能损害研究结果和可重复性的医源性变化。