In order to combine high-quality research with minimal harm to animals, a prospective severity assessment for animal experiments is legally required in many countries. In addition, an assessment of the evidence-based severity level might allow realistic harm-benefit analysis and the appraisal of refinement methods. However, only a few examples describe the distress of animals by simple, cost-efficient, and noninvasive methods. We, therefore, evaluated the severity of an orthotopic mouse model for pancreatic cancer using C57BL/6J mice when pursuing two different chemotherapies. We assessed fecal corticosterone metabolites, body weight, distress score, and burrowing, as well as nesting activity. Moreover, we established a multifactorial model using multivariate logistic regression to describe animal distress. This multifactorial analysis revealed that metformin + galloflavin treatment caused higher distress than metformin + α-cyano-4-hydroxycinnamate therapy. Similar results were obtained by using the best cutoff calculated by Youden's J index when using only single parameters, such as burrowing activity or fecal corticosterone metabolite concentration. Thus, the present study revealed that single readout parameters, as well as multivariate analysis, can help to assess the severity of animal experiments and detect side effects of therapies.

中文翻译：

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对动物的痛苦和治疗的副作用进行分级

为了将高质量的研究与对动物的伤害最小化相结合，许多国家/地区的法律要求对动物实验进行前瞻性的严重程度评估。此外，对基于证据的严重性级别的评估可能允许进行现实的危害-收益分析和改进方法的评估。然而，只有少数例子描述了通过简单、经济、无创的方法来描述动物的痛苦。因此，我们在进行两种不同的化疗时，使用 C57BL/6J 小鼠评估了胰腺癌原位小鼠模型的严重程度。我们评估了粪便皮质酮代谢物、体重、窘迫评分、挖洞以及筑巢活动。此外，我们使用多元逻辑回归建立了一个多因素模型来描述动物的窘迫。该多因素分析显示，二甲双胍 + 鸡黄素治疗比二甲双胍 + α-氰基-4-羟基肉桂酸酯治疗引起更高的痛苦。当仅使用单个参数（如挖洞活动或粪便皮质酮代谢物浓度）时，通过使用 Youden's J 指数计算的最佳截断值获得了类似的结果。因此，本研究表明，单一读数参数以及多变量分析可以帮助评估动物实验的严重程度并检测治疗的副作用。