Careful planning and implementation of humane endpointsHumane endpoint The moment in the experiment at which pain and/or distress experienced by the investigational animal is ended or alleviated by either killing the animal humanely or by discontinuing the procedure. requires a certain measure of expertise. Prior to the start of the experiment, its course must be anticipated and a decision about when to implement a humane endpointHumane endpoint The moment in the experiment at which pain and/or distress experienced by the investigational animal is ended or alleviated by either killing the animal humanely or by discontinuing the procedure. must be reached.
The exact time of the endpoint is dependent on the objective of the experiment, but it should be chosen before the onset of distressDistress It indicates a disadvantageous environment in which the animal is no longer able to adapt in a biologically successful manner to the stressors to which it is exposed. One speaks of distress when the level or the duration of stress are such that significant changes in biological function are required to survive. or as soon as possible thereafter. Preferably, the endpoint is chosen on the basis of objective criteria. The remarks relating to moral and scientific considerations for humane endpoints, listed in the paragraph “Why humane endpoints?” should be kept in mind.
Before having identified the relevant endpoint, the following aspects have to be dealt with:
- a test analysis on critical steps in terms of painPain The negative sensory or emotional experience that indicates awareness in the animal of injury or the threat of injury to the body. This negative experience induces changes in an animal’s behavior and physiology, intended to limit the effect of, or avoid the injury, to reduce the chances of repeated injury and to promote recovery. and distress;
- identification and evaluation of potential endpoints;
- validation of selected endpoints;
- acceptance of the selected endpoints by users (e.g. principle investigators or, in case of regulatory tests; the relevant authorities).
Dependent of the experiment the endpoints (ideally) satisfy the following criteria:
- easy to monitor;
- reproducible;
- not labor-intensive;
- valid prediction of disease progression;
- relevant (equivalent) and robust (little variation);
- maximal reduction of pain and discomfortDiscomfort A state of pain and distress in laboratory animals..
In practical terms, the following three steps must be taken to arrive at suitable humane endpoints:
- objective definition and registration of signs of pain and distress in the experiment;
- selection based on the significance of these signs;
- assurance of the scientific validity (largely meets the above-mentioned criteria).
