Incorporating inter-individual variability in experimental design improves the quality of results of animal experiments

• Published in: PloS one Vol. 16; no. 8; p. e0255521
• Main Authors: van der Goot, Marloes H, Kooij, Marieke, Stolte, Suzanne, Baars, Annemarie, Arndt, Saskia S, van Lith, Hein A
• Format: Journal Article
• Language: English
• Published: San Francisco, CA USA Public Library of Science 05.08.2021; Public Library of Science (PLoS)
• Subjects: Analysis; Animal behavior; Animal experimentation; Biology and Life Sciences; Evaluation; Medicine and Health Sciences; Methods; Pharmacology, Experimental; Research and Analysis Methods; Social Sciences; Netherlands
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0255521

Inter-individual variability in quantitative traits is believed to potentially inflate the quality of results in animal experimentation. Yet, to our knowledge this effect has not been empirically tested. Here we test whether inter-individual variability in emotional response within mouse inbred strains affects the outcome of a pharmacological experiment. Three mouse inbred strains (BALB/c, C57BL/6 and 129S2) were behaviorally characterized through repeated exposure to a mild aversive stimulus (modified Hole Board, five consecutive trials). A multivariate clustering procedure yielded two multidimensional response types which were displayed by individuals of all three strains. We show that systematic incorporation of these individual response types in the design of a pharmacological experiment produces different results from an experimental pool in which this variation was not accounted for. To our knowledge, this is the first study that empirically confirms that inter-individual variability affects the interpretation of behavioral phenotypes and may obscure experimental results in a pharmacological experiment.