Severity assessment of scientific procedures performed on laboratory animals. Theoretical and applied aspects

Original article

УДК 636.028+57.084:59.08
DOI: 10.57034/2618723X-2022-04-07

Е.А. Kushnir1*, Candidate of Biological Sciences, Head of Quality Assurance Department,
М.V. Belopolskaya1, Candidate of Biological Sciences, Leading Researcher, Quality Assurance Department of the Vivarno-Experimental Complex,
V.S. Popov2, Candidate of Biological Sciences, Head of the Laboratory of Translational Medicine,
М.L. Lovat3, Candidate of Biological Sciences, Leading Researcher,

1 “Institute of Mitoengineering MSU” LLC,
119234, Russia, Moscow, Leninskie Gory, 1, bld. 73;
2 Faculty of Medicine of M.V. Lomonosov MSU,
119234, Russia, Moscow, Leninskie Gory, 1;
3 Biological faculty of M.V. Lomonosov MSU,
119234, Russia, Moscow, Leninskie Gory, 1, bld 12.

* Е-mail: [email protected]

Keywords: the 3Rs prospective and retrospective severity assessment selection of criteria for the actual severity assessment assessment score-sheets “non-recovery” humane endpoints


The study was performed without external funding.

For citation:

Kushnir Е.А., Belopolskaya М.V., Popov V.S., Lovat М.L. Severity assessment of scientific procedures performed on laboratory animals. Theoretical and applied aspects. Laboratory Animals for Science. 2022; 4.


This publication is an explanation of the practical application of the requirements of Directive 2010/63/EU to the continuous severity assessment of the animal experiments.

According to modern bioethical requirements formulated in Directive 2010/63/EU, prolonged severe pain and suffering that the experimental animal cannot avoid is unacceptable. In order to meet this requirement, all procedures on animals should be assigned a severity classification (“mild”, “moderate”, “severe or non-recovery”). This should be done while planning the experiment prior to performing any procedure (the prospective severity classification). Prospective severity classification of procedures facilitates the optimization of the experimental design to implement the least constraining procedures, foresee the methods for the animals’ distress, pain, suffering relief and prevent their sudden death. During the study, all abnormalities in the animals’ condition as well as the necessary measures for the pain alleviation are recorded using the prepared welfare assessment score sheets; the humane euthanasia is carried out, if necessary, which allows to keep the level of severity of procedures the lowest possible.

By the end of study the actual severity experienced during the entire experiment by each individual animal is assessed and the measures that have been taken for the prevention of the exceeding the prospective severity level are analyzed. This actual severity of any previous procedure is on top a key consideration in determining whether or not an animal can be re-used in further procedures (if acceptable in this study) and aids in determining the retrospective severity classification, to be assigned at the end of a project as the cumulative severity of the entire study. The results of the actual severity analysis are to be included into the study report, may be requested by the Bioethics Commission, and serve as a starting point for the corrective actions in future similar studies. These three steps of the severity classification offer opportunities to implement the principles of 3R’s aimed at improving animal welfare and increase the quality of experimental animal studies facilitating the formation of common modern standards in laboratory animal science.

The technology of the continuous severity assessment of the animal experiments haven’t been previously applied and published in Russia.

Conflict of interest

The authors declare no conflict of interest.

Authors contribution

E.A. Kushnir — concept and the text writing.
M.V. Belopolskaya — collection, analysis and the interpretation of the experimental data.
V.S. Popov — critical review of the content of the article.
M.L. Lovat — responsibility for all aspects of the work, proper study and resolution of issues related to the reliability of data or the integrity of all parts of the article, literary editing, approval of the final version of the article for publication.


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Received: 2022-09-23
Reviewed: 2022-10-18
Accepted for publication: 2022-11-01

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