Perceptions of 3R implementation in European animal research: A systematic review, meta-analysis, and meta-synthesis of barriers and facilitators

Objectives: The purpose of this systematic review was to examine how the scientific community in Europe that is involved with research with animals perceives and experiences the implementation of 3R (Replace, Reduce, Refine). Methods: A systematic search of the literature published in the past ten years was performed in PubMed, Web of Science and Scopus. Publications were screened for eligibility using a priori inclusion criteria, and only empirical evidence (quantitative, qualitative, or mixed methodologies) was retained. Quantitative survey items were investigated by conducting a meta-analysis, and the qualitative data was summarized using an inductive meta-synthetic approach. Included publications were assessed using the Quality Assessment for Diverse Studies tool. Results: 17 publications were included (eight quantitative, seven qualitative, two mixed-methods). The meta-analysis revealed that scientists are skeptical about achieving replacement, even if they believe that 3R improve the quality of experimental results. They are optimistic concerning the impact of 3R on research costs and innovation, and see education as highly valuable for the implementation of 3R. The meta-synthesis revealed four barriers (systemic dynamics, reification process, practical issues, insufficient knowledge) and four facilitators (efficient use of animals, caring for animals, regulatory uptake, supportive workplace environment). Conclusion: These findings show actionable levers at the local and systemic levels, and may inform regulators and institutions in their 3R policies. Trial registration: The protocol was registered into the PROSPERO database under the number CRD42023395769.