Identifying more clinically effective analgesic regimens and potential strain differences in pain perception in mice using a novel Operant Pain Assay

该项目旨在改善对在科学研究中经历潜在痛苦程序的实验室小鼠的疼痛缓解。我们估计，每年约有13%(约40万英国，全球400万)用于研究的小鼠将经历潜在的痛苦程序，在这些程序中，有效的疼痛缓解可以减少或防止所经历的疼痛。不幸的是，目前给小鼠服用的许多止痛药似乎部分或完全无效。这对动物福利和从这些小鼠收集的科学数据的价值来说都是一个重大挑战。为了改善小鼠的疼痛缓解，我们需要：-一种更好的方法来测试止痛药物在治疗程序相关疼痛方面的有效性。-确定新的止痛药是否比目前使用的更好。-确定在不同品系的小鼠之间观察到的止痛药有效性的差异是否与潜在疼痛体验的差异有关。要回答这些基本问题，我们有两个相互关联的目标。目的1建立常规使用和新的止痛药在三个常见品系的实验小鼠身上的有效性。这将分三个阶段完成，这将确保使用最少数量的小鼠，并使这些小鼠暴露在可能实现目标的最轻微的痛苦中。第一阶段将使用一种新的自动化方法(口腔手术止痛法)，快速评估目前使用的和新的止痛药在最常见的小鼠品系中的有效性。这被认为比目前使用的方法更好，因为它只产生一种温和而短暂的疼痛刺激，小鼠能够关闭这种刺激，并且是实际手术后感受到的疼痛的更好模型。第二阶段将测试第一阶段确定的三种最有效药物在另外两个常见品系的小鼠身上的有效性。第三阶段将测试三种最有效的止痛形式(从第一阶段到第二阶段)在治疗相同普通品系的小鼠手术后疼痛方面的有效性。作为育种计划的一部分，这些小鼠将接受常规的输精管结扎术，并将使用一系列有效的小鼠疼痛措施来测试止痛药的有效性，这些措施包括：自发行为(如行走和站立)，是否存在与疼痛有关的行为(如抽搐和扭动)，与疼痛有关的面部表情，以及筑巢和挖洞的意愿和能力(与生俱来的老鼠行为)。药物的有效性将通过确定哪种药物(S)恢复和维持正常的行为模式并减少疼痛相关行为的表达来确定。目标2将确定在本项目中使用的常见小鼠品系之间所经历的疼痛是否潜在不同。使用阶段1和阶段2的口腔面部操作员疼痛分析数据使我们能够调查这些小鼠的疼痛体验，因为它要求每只小鼠平衡它们寻求美味奖励的动机和它们感觉到的轻微疼痛。如此复杂的任务不能用简单的反射反应来完成，因为这些反应并不依赖于动物有意识地经历疼痛。使用第三阶段的手术后数据，我们能够确定手术后疼痛相关行为表达的品系差异是否与在第一阶段和第二阶段观察到的奖赏寻求品系的差异相关。这使我们能够确定这些差异是否潜在地与品系之间的疼痛体验差异有关。该项目将确定哪种止痛药对特定类型(品系)的小鼠最有效，遵循常规使用的手术程序，允许提出并实施建议，以改善用于科学研究的小鼠的福利和对这些动物进行的科学质量。

This project aims to improve the pain relief administered to laboratory mice that undergo potentially painful procedures in scientific research. We estimate that annually ~13% (~400k UK, >4 million worldwide) of mice used in research, will undergo potentially painful procedures where effective pain relief could reduce or prevent the pain experienced. Unfortunately, many of the current pain relieving drugs administered to mice appear to be partially or completely ineffective. This represents a major challenge for both animal welfare and the value of the scientific data collected from these mice. To achieve improved pain relief for mice we need:- A better means of testing pain-relieving drugs for their effectiveness in treating procedure-related pain. - To determine whether new pain-relieving drugs are better than those currently being used. - To determine whether or not the differences in the effectiveness of pain-relieving drugs observed between mouse strains relates to differences in the underlying experience of pain. To answer these fundamental questions, we have two interlinked objectives. Objective 1 will establish the effectiveness of routinely used and new pain-relieving drugs in three common strains of laboratory mice. This will be accomplished in 3 stages, which will ensure that the minimum number of mice are used, and that those mice are exposed the mildest pain possible to achieve of the objectives. Stage 1 will rapidly assess the effectiveness of currently used and new painkillers in the most common strains of mice using a new automated method (Orofacial Operant Pain Assay). This is considered better than currently used methods as it only produces a mild and short-lived painful stimulus that the mouse is able switch off and is a better model of the pain experienced after an actual procedure. Stage 2 will test the effectiveness of the three most effective drugs identified in stage 1 in two other common strains of mice. Stage 3 will test the effectiveness of the three most effective forms of pain-relief (from stages 1 & 2) in treating post-surgical pain in the same common strains of mice. These mice will be undergoing routine vasectomy as part of a breeding programme and the effectiveness of pain-relieving drugs will be tested using a range of validated pain measures for mice, including: spontaneous behaviour (e.g. walking and rearing), presence of pain-related behaviours (e.g. twitching and writhing), pain-related facial expressions, and the willingness and ability to nest build and burrow (innate mouse behaviours). The effectiveness of the drugs will be determined by identifying which drug(s) restore and maintain normal patterns of behaviour and reduce the expression of pain-related behaviours.Objective 2 will establish whether the pain experienced potentially differs between the common mouse strains being used in this project. Using the Orofacial Operant Pain Assay data from stages 1 and 2 allows us to investigate pain experience in these mice because it asks each mouse to balance their motivation to seek palatable reward against the mild pain they perceive. Such a complex task cannot be accomplished with a simple reflex response since these are not dependent on the animal consciously experiencing the pain. Using the post-surgical data from stage 3 enables us to determine whether strain differences in the expression of pain related behaviours following surgery correlate with strain differences in reward seeking observed at stages 1 and 2. This enables us to determine if the differences are potentially related to differences in pain experience between the strains.This project will determine which pain relieving drugs are the most effective, for a specific type (strain) of mouse following a routinely used surgical procedure allowing recommendations to be made and implemented to improve the welfare of mice used in scientific research and the quality of the science carried out on these animals.