Animal experiments remain indispensable in basic biomedical research, but must be ethically justified and supplemented by alternative methods, as researchers at the Max Planck Institutes emphasize. At the Max Planck Institute for Biological Cybernetics in Tübingen, researchers are guided by the extended 4Rs principle, which emphasizes not only the reduction, improvement and replacement of animal experiments but also the personal responsibility of scientists, explained PD Dr. Thomas Ott, responsible for neuroscientific models and animal research. “At the Max Planck Institutes, we are committed to improving the social life of animals, further developing tools to determine their sentience, consciousness and intelligence and actively leading the public debate on animal ethics,” emphasized Ott.

Animal experiments are an emotional topic, as they often seem difficult to understand, it said. Computer-aided models, cell-based cultures or studies on humans, for example on the role of sleep in memory formation, could already be used in basic research. However, for complex issues, such as research into Alzheimer’s or Parkinson’s disease, experiments on vertebrates such as mice or zebrafish are necessary, as they are the only way to realistically depict the electrophysiological and biochemical processes of the brain. “The basic blueprint of a mouse differs only slightly from ours. This makes it possible to investigate the genetic causes of unbalanced biochemical processes by specifically switching off genetic information in mice. In this way, conclusions can be drawn about humans,” explained Ott. The genetic match of up to 95 percent makes mice particularly valuable, for example for the development of precise therapies.

Zebrafish also play a central role, particularly in behavioral research, the researchers explained. Thanks to their transparent skull in the larval stage, a special light microscope makes it possible to observe processing in the brain in real time. “For behavioral research like this, it is particularly important that the animals feel comfortable and that their perception corresponds to that of a natural living environment. Any deviation due to negative influencing factors would distort the collected behavioral data or render it unusable,” Ott emphasized. The fish are kept in small aquariums to avoid social stress or rivalry.

Alternative methods such as organ-on-a-chip technology, in which organ-like structures are grown from stem cells, offer promising approaches, for example in drug development. “Bio-chips are already delivering promising results in drug development, for example by testing the effect of an active ingredient directly on organoids. This shows whether a substance affects the cell tissue – but conversely, it cannot be ruled out that substances that are inconspicuous in the model may still cause damage in a human organism,” warned Ott. Complex processes such as emotions or hormonal interactions cannot currently be mapped, and only a few cell types grow in culture.

The 4Rs principle – reduction, refinement, replacement and responsibility – is prescribed by law and sets high ethical standards, the researchers emphasized. “The consistent implementation of these principles in all areas of animal research is ultimately the prerequisite for animal experiments to be approved by the relevant authorities,” explained Ott. Nevertheless, it is currently not possible to completely dispense with animal experiments, as even the validation of organ-on-a-chip results requires animal experiments. Transparency about the opportunities and limitations of alternative methods is crucial in order to avoid false expectations, the scientists concluded.

Read also:

3R shows effect: number of animal experiments decreases – MedLabPortal

Replacing animal testing: 3R network continues to grow – MedLabPortal

PRESENTED: Maike Frye and the three Rs – MedLabPortal

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