Faculty of Medicine, Institute for Laboratory Animal Science and Experimental Surgery, RWTH Aachen University, Aachen, Germany.
Institute of Imaging and Computer Vision, RWTH Aachen University, Aachen, Germany.
Sci Rep. 2022 Jun 28;12(1):10910. doi: 10.1038/s41598-022-14852-0.
Despite its long establishment and applicability in mice pain detection, the Mouse Grimace Scale still seems to be underused in acute pain detection during chronic experiments. However, broadening its applicability can identify possible refinement approaches such as cumulative severity and habituation to painful stimuli. Therefore, this study focuses on two main aspects: First, five composite MGS criteria were evaluated with two independent methods (the MoBPs algorithm and a penalized least squares regression) and ranked for their relative importance. The most important variable was used in a second analysis to specifically evaluate the context of pain after an i.p. injection (intervention) in two treatment groups (CCl and oil (control)) at fixed times throughout four weeks in 24 male C57BL/6 N mice. One hour before and after each intervention, video recordings were taken, and the MGS assessment was performed. In this study, the results indicate orbital tightening as the most important criterion. In this experimental setup, a highly significant difference after treatment between week 0 and 1 was found in the CCl group, resulting in a medium-sized effect (W = 62.5, p value < 0.0001, r = 0.64). The oil group showed no significant difference (week 0 vs 1, W = 291.5, p value = 0.7875, r = 0.04). Therefore, the study showed that the pain caused by i.p. injections was only dependent on the applied substance, and no significant cumulation or habituation occurred due to the intervention. Further, the results indicated that the MGS system can be simplified.
尽管在小鼠疼痛检测中已经长期确立并适用，但在慢性实验中的急性疼痛检测中，老鼠面部表情评分量表似乎仍未得到充分应用。然而，拓宽其适用性可以确定可能的改进方法，例如累积严重程度和对疼痛刺激的习惯化。因此，本研究主要关注两个方面：首先，使用两种独立方法（MoBPs 算法和惩罚最小二乘回归）评估了五个综合 MGS 标准，并对其相对重要性进行了排名。使用最重要的变量进行了第二次分析，专门评估了在 24 只雄性 C57BL/6N 小鼠中，在四周内的四个固定时间点，对腹腔注射（干预）后的疼痛背景进行评估，分为两个治疗组（CCl 和油（对照））。在每次干预前后一个小时，进行视频记录，并进行 MGS 评估。在本研究中，结果表明眼眶收紧是最重要的标准。在这种实验设置中，在 CCl 组中，在治疗后第 0 周和第 1 周之间发现了非常显著的差异，导致中等大小的效应（W=62.5，p 值<0.0001，r=0.64）。油组没有显示出显著差异（第 0 周与第 1 周，W=291.5，p 值=0.7875，r=0.04）。因此，该研究表明，腹腔注射引起的疼痛仅取决于所应用的物质，由于干预，没有明显的累积或习惯化。此外，结果表明 MGS 系统可以简化。
