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3Rs – an important ethical principle
The 3Rs refer to replacement, refinement, and reduction.
Different perspectives
Today, the principles permeate research that includes animal experiments. Legislation in Sweden and the European Union is based on the 3Rs, which are of central importance in applications submitted to the Ethical Committees on Animal Experiments. The 3Rs provide a foundation for developing methods frequently referred to as alternative methods.
Because the body is so complex, it is difficult to completely replace animal research with other methods. Instead, such methods tend to complement research involving animal experiments. To date, the greatest progress has been achieved in the areas of refinement and reduction.
Replacement
The most radical solution involves replacing animals in research with methods that use no animals. Some advancements have been made during the past decade, e.g. in purity tests for insulin.
Previously, mice and rabbits were used to test whether insulin was sufficiently pure for human use. Today, chemical methods involving chromatography are used instead of animal experiments to analyse insulin. Cell cultures and computer simulations are other methods that have been used to replace some animal experiments – for instance, in determining how a substance affects a particular type of cell.
However, it is more difficult to replace animals when trying to observe how a substance influences the interaction of cells or entire organs in the body, or trying to map the complex mechanisms underlying a disease.
Refinement
Research methods are refined with the intent to minimise pain and other effects on animals. Methods can be refined in various ways, for instance using the most appropriate methods of anaesthesia and euthanasia.
Another important area is to improve the care and housing of animals so they are not exposed to stress, poor ventilation, or cramped spaces. Considerable progress has been made on this front in recent years. An example is the use of telemetry, which involves implanting a microchip in the animal. Using wireless technology, researchers can monitor physiological functions such as blood pressure and pulse without disturbing or anesthetising the animal.
Reduction
Research should be designed to yield the maximum amount of relevant information while using the minimum number of animals. For instance, researchers can use mathematical models to calculate how many animals are necessary to achieve statistical validity in the research results.
The number of animals used per experiment has also decreased in pace with improvements in their living conditions. Improved hygiene, better ventilation, and more space have contributed to healthier animals. Fewer become sick and need to be removed from an experiment.
Text: Karl-Johan Börjesson
Editor: Peter Tillhammar, Swedish Research Council. Contact: Send email to the editorial staff.
