Measurement of corticosterone in mice: a protocol for a mapping review

Abstract

Severity assessment for experiments conducted with laboratory animals is still based mainly on subjective evaluations; evidence-based methods are scarce. Objective measures, amongst which determination of the concentrations of stress hormones, can be used to aid severity assessment. Short-term increases in glucocorticoid concentrations generally reflect healthy responses to stressors, but prolonged increases may indicate impaired welfare. As mice are the most commonly used laboratory animal species, we performed a systematic mapping review of corticosterone measurements in Mus musculus, to provide a full overview of specimen types (e.g. blood, urine, hair, saliva, and milk) and analysis techniques. In this publication, we share our protocol and search strategy, and our rationale for performing this systematic analysis to advance severity assessment. So far, we have screened 13,520 references, and included 5337 on primary studies with measurements of endogenous corticosterone in M. musculus. Data extraction is currently in progress. When finished, this mapping review will be a valuable resource for scientists interested in corticosterone measurements to aid severity assessment. We plan to present the data in a publication and a searchable database, which will allow for even easier retrieval of the relevant literature. These resources will aid implementation of objective measures into severity assessment.

Reviewing the animal literature: how to describe and choose between different types of literature reviews

“…Publication of a protocol in a scientific journal has the added advantage of external peer review before starting the review efforts, which is expected to increase the quality of the work. Examples are Leenaars et al, 22 Matta et al, 23 Pires et al 24 and van Luijk et al 25 Developing a search and searching the literature…”

Behavioral Methods for Severity Assessment

“…review to analyze the frequencies of corticosterone sample types in mice and the different analysis techniques [25].…”

“…Glucocorticoids or their metabolites are commonly measured in blood [ 22 ], feces [ 23 ] or in hair samples [ 24 ]. Leenaars and colleagues performed a mapping review to analyze the frequencies of corticosterone sample types in mice and the different analysis techniques [ 25 ].…”

Alternate without alternative: neither preference nor learning explains behaviour of C57BL/6J mice in the T-maze

“…In a modification of the discrimination test, the T-maze is also used as a preference test: The arms are provided with different goods, and the animal is required to choose between them. This form of preference test seems to be easily performed with a variety of animal species (mice: Roder et al, 1996;Correa et al, 2015;Cutuli et al, 2015;wild mice: Nunes et al, 2009;rats: Patterson-Kane et al, 2001;Ras et al, 2002;Denk et al, 2004;van der Plasse et al, 2007;Cunningham et al, 2015;Hernandez-Lallement et al, 2015;Wadhera et al, 2017;Leenaars et al, 2019;pigs: Rooijen & Metz, 1987;hens: Dawkins, 1977;broilers: Buckley et al, 2011;zebrafish: Hieu et al, 2020; fruit flies: Fujita & Tanimura, 2011). Preference is usually assessed by offering the goods in the choice arms of the maze but in some cases, it might be useful to use stimuli which are associated with the to-be-tested goods instead, e.g., in tests for social preference, the real mouse might be replaced by urinary stimuli (Nunes et al, 2009; compare also Fitchett et al, 2006).…”