Improving the transparency of animal experiments: valuable lessons learned from a systematic analysis of registration protocols

To comprehensively analyze the epidemiological characteristics of research protocols on international animal experiment registration platforms, explore potential factors influencing protocol publication, and offer recommendations to improve animal experiment registration systems. Research protocols registered on the Netherlands’ PCT(Preclinical Trials) and Germany’s ASR(Animal Study Registry) animal experiment registration platforms up to December 30, 2024, were included. Relevant data were extracted, and frequency distributions and percentages were calculated to statistically describe the findings. Factors influencing publication rates were identified using chi-square tests and multivariate binary logistic regression analysis. A total of 272 registered protocols were analyzed, including 124 from the PCT platform and 148 from the ASR platform, originating from 31 countries, spanning 47 research areas, and involving 11 different animal species. Among the studies, 10.0% (27/272) did not report randomization, and none of the randomized studies (132/272) addressed allocation concealment. Additionally, 24.6% (67/272) and 35.3% (96/272) failed to report blinding during intervention implementation and outcome measurement, respectively. Only 43.3% (97/224) of the experiments were completed within the specified timeframe, and among these, merely 23.7% (23/97) achieved full publication. Animal species were identified as potential influencing factors. Studies using pigs as animal models were more frequently published. As a vital measure to enhance the quality of animal experiments, the registration of animal protocols requires joint emphasis and coordinated promotion by multiple stakeholders, including researchers, research institutions, ethics committees, journal editors, funding agencies, and regulatory authorities. Strengthening protocol registration will not only improve transparency, reproducibility, and ethical oversight, but also build a more trustworthy foundation for high-quality evidence and accelerate the clinical translation of animal research.