Fat accumulation in the rat heart during fasting

Area of Science:

• Cardiovascular Physiology
• Cellular Biology
• Histology

Background:

• Fasting induces lipid droplet accumulation (LDA) in various organs, including the heart.
• Understanding cardiac fat metabolism during short-term fasting is crucial for interpreting experimental results.

Purpose of the Study:

• To investigate age- and sex-dependent changes in cardiac lipid droplet accumulation (LDA) in rats following short-term food deprivation.
• To characterize the spatial distribution and temporal dynamics of LDA in different heart regions.

Main Methods:

• Male and female rats (6, 12, 18, 24 weeks) were fasted for 1, 2, or 3 days.
• Cardiac lipid droplets were quantified using Oil Red O staining and a standardized scoring system across defined heart regions.
• Histological sections of ventricles and atria were analyzed.

Main Results:

• LDA increased with fasting duration, typically peaking by day two, and rapidly decreased upon refeeding.
• Males generally exhibited greater LDA than females; deposition was maximal in the right and left ventricles, particularly superior regions.
• Younger and older rats (6, 12, 24 weeks) showed more pronounced LDA than 18-week-old rats, which had a minimal response.

Conclusions:

• Short-term fasting induces significant, regionally specific LDA in rat hearts, with rapid reversibility.
• Age and sex influence the extent of LDA, suggesting complex regulatory mechanisms.
• The findings underscore the impact of even brief fasting periods on cardiac histology and metabolism, necessitating careful consideration in research.