The assessment of exposure in animal testing is a central component of European and German legislation. However, the legally required, graduated assessment is made more difficult by the fact that there are not enough scientifically sound and quantifiable parameters available for the assessment of exposure. As part of a multicenter research project funded by the DFG (severity-assessment.de), suitable parameters and methods are being identified and tested on established animal models in order to create the basis for a scientifically sound and scalable assessment of the burden on laboratory animals in animal experiments. These are then compared across working groups and models.

In our working group, we develop evaluation schemes to assess the burden of intracranial interventions in established rat models of neurological diseases. This includes surgical interventions as well as the tests used in our laboratories to assess motor and cognitive functions, electrophysiological stimulation in the context of deep brain stimulation (DBS), neuronal recordings and the definition of human endpoints in brain tumors. For stress assessment, we combine classic clinical scores with analyses of species-specific spontaneous behavior. In addition, behavioral examinations in the area of motor function and the associative-limbic system as well as telemetric measurements of cardiac activity and movement behavior are used.

These examinations have already enabled us to create a gradation of the stress caused by intracranial interventions of varying complexity, systemic injections, behavioral tests and animal care measures. In addition, we have developed an algorithm based on individual weight progression that allows us to reliably determine the humane endpoint in a rat model with a brain tumor before the onset of severe stress.

This data will be used to optimize the postoperative pain protocol and to improve behavioral studies and housing conditions. Group housing in large, well-equipped cages with running wheels is also currently being tested.