The Directive 2010/63/EU on animal experimentation may skew the conclusions of pharmacological and behavioural studies

Abstract

All laboratory animals shall be provided some form of environmental enrichment (EE) in the nearest future (Directive 2010/63/EU). Displacing standard housing with EE entails the possibility that data obtained under traditional housing may be reconsidered. Specifically, while EE often contrasts the abnormalities of consolidated disease models, it also indirectly demonstrates that their validity depends on housing conditions. We mimicked a situation in which the consequences of a novel pharmacological compound were addressed before and after the adoption of the Directive. We sub-chronically exposed standard- or EE-reared adolescent CD1 mice (postnatal days 23-33) to the synthetic compound JWH-018, and evaluated its short- and long-term potential cannabinoid properties on: weight gain, locomotion, analgesia, motor coordination, body temperature, brain metabolism (1H MRI/MRS), anxiety- and depressive-related behaviours. While several parameters are modulated by JWH-018 independently of housing, other effects are environmentally mediated. The transition from standard housing to EE shall be carefully monitored.

An overview of maternal separation effects on behavioural outcomes in mice: Evidence from a four-stage methodological systematic review

“…For example, as of 2010, all laboratory animals in Europe must be provided with some form of environmental enrichment (Directive 2010/63/EU). This raises the possibility that all findings obtained under traditional housing conditions will need to be reconsidered, because the implementation of environmental enrichment might skew conclusions from behavioural and biological analyses (Macri et al, 2013). the cycle in which the test will be run (Jensen Pena and Champagne, 2013;Parfitt et al, 2007;Toki et al, 2007).…”

Maternal high-fat diet acts as a stressor increasing maternal glucocorticoids’ signaling to the fetus and disrupting maternal behavior and brain activation in C57BL/6J mice

“…Locomotor activity was monitored through an automatic device using small infrared sensors positioned on the top of each cage (ACTIVISCOPE system, NewBehaviour Inc., Zurich, Switzerland, Macri et al, 2013). The sensors detected any movement of mice (except when mice were asleep or inactive) with a frequency of 20 events per second (20 Hz).…”

Housing mice in the individually ventilated or open cages—Does it matter for behavioral phenotype?

“…However, within the strains the results can be influenced by sex and housing system depending on the behavioral tasks applied. 13 In addition, during last 10-15 years most of the newly built or renovated animal facilities are equipped with the individually ventilated caging (IVC) systems. Among many factors contributing to these problems, environment in its broad sense is certainly one of the major issues.…”