Overmyer Katherine A, Thonusin Chanisa, Qi Nathan R, Burant Charles F, Evans Charles R
Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, Michigan, United States of America.
Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan, United States of America.
PLoS One. 2015 Feb 6;10(2):e0117232. doi: 10.1371/journal.pone.0117232. eCollection 2015.
A critical application of metabolomics is the evaluation of tissues, which are often the primary sites of metabolic dysregulation in disease. Laboratory rodents have been widely used for metabolomics studies involving tissues due to their facile handing, genetic manipulability and similarity to most aspects of human metabolism. However, the necessary step of administration of anesthesia in preparation for tissue sampling is not often given careful consideration, in spite of its potential for causing alterations in the metabolome. We examined, for the first time using untargeted and targeted metabolomics, the effect of several commonly used methods of anesthesia and euthanasia for collection of skeletal muscle, liver, heart, adipose and serum of C57BL/6J mice. The data revealed dramatic, tissue-specific impacts of tissue collection strategy. Among many differences observed, post-euthanasia samples showed elevated levels of glucose 6-phosphate and other glycolytic intermediates in skeletal muscle. In heart and liver, multiple nucleotide and purine degradation metabolites accumulated in tissues of euthanized compared to anesthetized animals. Adipose tissue was comparatively less affected by collection strategy, although accumulation of lactate and succinate in euthanized animals was observed in all tissues. Among methods of tissue collection performed pre-euthanasia, ketamine showed more variability compared to isoflurane and pentobarbital. Isoflurane induced elevated liver aspartate but allowed more rapid initiation of tissue collection. Based on these findings, we present a more optimal collection strategy mammalian tissues and recommend that rodent tissues intended for metabolomics studies be collected under anesthesia rather than post-euthanasia.
代谢组学的一项关键应用是对组织进行评估，而组织往往是疾病中代谢失调的主要部位。实验室啮齿动物因其易于操作、具有遗传可操控性且在大多数人类代谢方面与人类相似，已被广泛用于涉及组织的代谢组学研究。然而，尽管麻醉可能会导致代谢组发生改变，但在为组织采样做准备时进行麻醉这一必要步骤却常常未得到充分考虑。我们首次使用非靶向和靶向代谢组学方法，研究了几种常用的麻醉和安乐死方法对采集C57BL/6J小鼠骨骼肌、肝脏、心脏、脂肪和血清的影响。数据显示了组织采集策略对不同组织产生的显著影响。在观察到的众多差异中，安乐死后采集的样本显示骨骼肌中6-磷酸葡萄糖和其他糖酵解中间产物水平升高。在心脏和肝脏中，与麻醉动物相比，安乐死动物组织中多种核苷酸和嘌呤降解代谢产物有所积累。脂肪组织受采集策略的影响相对较小，不过在所有组织中均观察到安乐死动物体内乳酸和琥珀酸的积累。在安乐死前进行的组织采集方法中，与异氟烷和戊巴比妥相比，氯胺酮表现出更大的变异性。异氟烷会导致肝脏天冬氨酸水平升高，但能使组织采集更快开始。基于这些发现，我们提出了一种更优化的哺乳动物组织采集策略，并建议用于代谢组学研究的啮齿动物组织应在麻醉状态下而非安乐死后采集。
