Replacement in the Laboratory

According to the EU Directive on Animal Experiments (RL 2010/63/EU), the replacement of procedures in which live animals are used for scientific purposes and the promotion of the development of alternative methods are the ultimate goals to be achieved. This objective is based on the principle of replacement, one of the 3Rs (Replacement, Reduction, Refinement) of Russell and Burch. Replacement ensures the use of animal-free alternative methods. This term includes not only the avoidance of the use of live animals in experiments, but also of products derived from them. In everyday laboratory work, some reagents are used for which animals are required. For example, products such as FCS/FBS (fetal calf serum/fetal bovine serum), Matrigel™ or the frequently used monoclonal or polyclonal antibodies are of animal origin.¹

FBS is the main component of many cell culture media. It contains hormones, vitamins, transport proteins, growth factors and many other ingredients needed for cell growth. To extract the serum, hearts of fetuses that are at least in the second trimester of gestation are punctured. No anesthesia is used for this procedure, although it is believed that this procedure is potentially painful for embryos. It is estimated that around two million calf fetuses are used for this purpose each year. Matrigel™, also known as Geltrex™ or Cultrex™, is another ingredient required for cell culture. It represents a protein matrix that requires the murine cell line of Engelbreth-Holm-Swarm sarcoma for its production. Monoclonal and polyclonal antibodies are also obtained from animals immunized to a specific antigen. These are then used for immunoassays such as ELISA and other immunohistochemical procedures.²

Apart from the objective of the EU Directive, as well as a moral-ethical responsibility towards laboratory animals, it is also justifiable from a scientific point of view to resort to substitute products. One factor of many, which contributes to the crisis of reproducibility in science, is actually said to result from the use of animal products in everyday laboratory work. The fact that these are obtained from different donor animals means that they cannot have an identical composition and consequently a uniform quality. Another point is that products of animal origin may contain unknown components and contamination cannot be completely ruled out. The totality of these factors ultimately leads to non-uniform materials, which represent a variable for the experiments and thus contribute to a reduction in reproducibility.⁴

For the purpose of maximizing research quality and animal welfare, it must be the goal of the entire scientific community to develop and establish suitable substitute products. Thus, it is the responsibility of all those involved in research to avoid animal products and to use animal-free materials instead.

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3) Habanjar O, Diab-Assaf M, Caldefie-Chezet F, Delort L. 3D cell culture systems: tumor application, advantages, and disadvantages, Int. J. Mol. Sci. 22 (2021), https://doi.org/10.3390/ijms222212200. Thakuri PS, Liu C, Lucker GD, Tavana H. Biomaterials-based approaches to tumor spheroid and organoid modeling, Adv. Healthc. Mater. 7 (2018), 170980, https://doi.org/10.1002/adhm.201700980. Kinzebach S, Bieback K. Expansion of mesenchymal stem/stromal cells under xenogenic-free culture conditions. Adv Biochem Eng Biotechnol 2013; 129: 33–57. Cassotta M, Bartnicka JJ, Pistollato F, Parvatam S, Weber T, D'Alessandro V, Bastos LF, Coecke S. A worldwide survey on the use of animal-derived materials and reagents in scientific experimentation. Eng Life Sci. 2022 Jul 18;22(9):564-583. doi: 10.1002/elsc.202100167. PMID: 36093359; PMCID: PMC9444711.

4) Cassotta M, Bartnicka JJ, Pistollato F, Parvatam S, Weber T, D'Alessandro V, Bastos LF, Coecke S. A worldwide survey on the use of animal-derived materials and reagents in scientific experimentation. Eng Life Sci. 2022 Jul 18;22(9):564-583. doi: 10.1002/elsc.202100167. PMID: 36093359; PMCID: PMC9444711.