Systematic Review Centre for Laboratory Animal Experimentation (SYRCLE)

The Systematic Review Centre for Laboratory Animal Experimentation (SYRCLE) was based in Nijmegen, The Netherlands. Its mission was to develop, apply and disseminate the methodology of systematic reviews of animal studies to advance responsible animal-based research by synthesis of evidence.

Founded in 2012 by Merel Ritskes-Hoitinga, SYRCLE had a network of ambassadors to facilitate collaboration with researchers, legislators and other stakeholders on systematic reviews of animal studies. The SYRCLE ambassador network is currently dormant, but individual ambassadors continue their activity (e.g. Gabriel Pires who co-founded BRISA, the Brazilian Reproducibility Initiative in preclinical Systematic review and meta-Analysis). Merel Ritskes-Hoitinga is a Board Member of Evidence Synthesis International (see also ESI's initial Position Statement).

The work is now being carried on by a Meta-Research team at Radboud University Medical Centre in Nijmegen.

In a systematic review, all research evidence relevant to a specific question is identified, selected, appraised and synthesized in order to enable evidenced-based decisions. A systematic review can contain a meta-analysis, where the results of several independent studies are statistically combined to calculate the average effect of two or more studies addressing the same question in more or less the same way.

SYRCLE published A step-by-step guide to systematically identify all relevant animal studies. The Guide contained detailed instructions on how to develop a comprehensive search strategy. Search filters for PubMed and for Embase have been developed. These search filters facilitate finding all animal studies on a specific topic. An updated Embase filter has been published.

The conduct of high-quality SR is also hampered by the lack of reporting of essential details in animal studies. SYRCLE therefore also developed the Gold Standard Publication Checklist (GSPC), which sets out in detail what a scientist should consider when reporting and designing an animal experiment (e.g. housing conditions, nutrition, drinking water supply and details of the intervention). The GSPC is easy to use and particularly suitable for making systematic reviews of animal studies more feasible. SYRCLE recommends the checklist to all scientists involved in animal experimentation and editors of journals publishing animal studies.

The extent to which a systematic review can draw reliable conclusions depends on the validity of the results of the included studies. SYRCLE developed a tool to assess the risk of bias in the included animal studies. SYRCLE's Risk of Bias tool is based on the Cochrane Risk of Bias tool and is adjusted for particular aspects of bias playing a role in animal intervention studies.

More information about systematic reviews and literature searches is available in a separate section of Norecopa's website.

Further reading

Menon et al. (2021): The impact of conducting preclinical systematic reviews on researchers and their research: A mixed method case study.