Seasonal Variation of Laboratory Animals as a Consideration for Research Reproducibility

Area of Science:

• Laboratory animal science
• Chronobiology
• Research methodology

Background:

• Standardized laboratory conditions aim to minimize extrinsic factors affecting research.
• Variability in research results can still arise despite standardization efforts.
• Seasonal changes represent a potential extrinsic factor influencing research reproducibility.

Purpose of the Study:

• To explore the existing literature on the impact of seasonal variability on research results.
• To discuss the potential influence of seasonal changes and internal clock mechanisms on animal models.
• To speculate on how seasonal variations in personnel might affect animal physiology and behavior.

Main Methods:

• Literature review of studies examining seasonal influences on laboratory animals.
• Discussion of the interplay between seasonal cycles and internal biological clocks.
• Exploration of potential indirect effects mediated by animal care personnel.

Main Results:

• Seasonal variability is a potential confounder in laboratory research.
• Internal biological clocks may interact with seasonal changes, but mechanisms are unclear.
• Seasonal changes in human handlers could induce physiological and behavioral alterations in rodents.

Conclusions:

• Seasonal variability poses a challenge to research reproducibility in laboratory rodents.
• Further research is needed to elucidate the mechanisms linking seasonal changes, internal clocks, and animal outcomes.
• Investigating the impact of personnel seasonality on animal models is warranted.