RNAseq Analysis of Rodent Spaceflight Experiments Is Confounded by Sample Collection Techniques

Area of Science:

• Space biology
• Transcriptomics
• Animal models in research

Background:

• Understanding physiological changes during spaceflight is crucial.
• Sample collection in space presents unique challenges.
• Previous studies may be affected by experimental variables.

Purpose of the Study:

• To identify confounding factors in spaceflight research.
• To assess the impact of tissue preservation on transcriptomic data.
• To improve the design of future space biology experiments.

Main Methods:

• Mice were housed on the International Space Station (ISS).
• Tissues were dissected and preserved either on-orbit or after return to Earth.
• Transcriptomic analysis was performed on collected samples.
• Follow-on experiments investigated euthanasia, preservation, and library preparation methods.

Main Results:

• Tissue preservation methods caused significant transcriptomic changes.
• Preservation-induced alterations overshadowed spaceflight-specific effects.
• Differences were amplified by polyA selection in library preparation.
• Euthanasia and preservation protocols introduced confounding variables.

Conclusions:

• Tissue preservation protocols are critical confounding factors in spaceflight transcriptomic studies.
• Current methods may obscure true spaceflight-induced physiological changes.
• Future experiments require standardized and validated preservation techniques.