Refinement Measure Using NMR for Subcutaneous Fat Mass Determination in Rats

Area of Science:

• Physiology
• Animal Science
• Biotechnology

Background:

• White adipose tissue (WAT) is crucial for energy homeostasis and is categorized into subcutaneous and visceral depots.
• Nuclear magnetic resonance (NMR) is a technique for measuring adipose tissue, but it can be stressful for live animals.
• Accurate quantification of WAT depots is essential for understanding metabolic health and the effects of diet.

Purpose of the Study:

• To validate the use of NMR for determining subcutaneous WAT weight in sacrificed rats.
• To assess the correlation between in vivo and ex vivo WAT measurements.
• To evaluate the efficacy of NMR in differentiating WAT depots across varying adiposity levels.

Main Methods:

• Rats were subjected to different dietary conditions, including a standard diet and a cafeteria diet.
• WAT measurements were performed on live rats using NMR.
• Post-sacrifice, WAT depots (subcutaneous and visceral) were weighed, and NMR was used to assess carcass WAT composition.

Main Results:

• NMR measurements of WAT in live rats and post-sacrifice carcass WAT showed comparable results in rats fed a standard diet.
• Across three dietary groups with differing adiposity, the percentage of subcutaneous and visceral WAT, as measured by NMR and direct dissection, remained consistent.
• NMR accurately reflected subcutaneous WAT composition regardless of the animal's overall adiposity.

Conclusions:

• Determining subcutaneous WAT weight via NMR in sacrificed rats is a valid and reliable approach.
• This NMR-based method provides a non-aversive alternative for assessing WAT, particularly subcutaneous WAT, in research settings.
• The findings support the use of NMR for quantitative analysis of WAT depots in animal models, irrespective of adiposity levels.