Systemic and tissue-specific spexin response to acute treadmill exercise in rats

Area of Science:

• Exercise Physiology
• Metabolic Regulation
• Endocrinology

Background:

• Spexin (SPX) is a peptide hormone involved in metabolism and energy balance.
• Exercise-induced molecules, or exerkines, mediate the health benefits of physical activity.
• The effect of acute exercise on circulating SPX levels and its tissue expression remains largely unknown.

Purpose of the Study:

• To investigate the impact of acute treadmill exercise on plasma SPX levels in rats.
• To examine the effects of acute exercise on SPX mRNA expression in skeletal muscle (soleus and EDL), adipose tissue, and liver.
• To assess changes in SPX protein levels in these tissues using immunohistochemistry.

Main Methods:

• Male Sprague Dawley rats were subjected to a 60-minute treadmill exercise session.
• Blood and tissue samples (soleus, EDL, adipose, liver) were collected at multiple time points post-exercise (0-24 hours).
• Plasma SPX levels were measured, alongside mRNA expression and immunohistochemical analysis of SPX in tissues.

Main Results:

• Acute exercise significantly increased plasma SPX levels.
• SPX mRNA expression was upregulated in the soleus, EDL, and liver following exercise.
• Liver SPX immunostaining decreased post-exercise, suggesting potential release into circulation.

Conclusions:

• Acute exercise induces an increase in circulating spexin, positioning it as a potential exerkine.
• The liver may be a source of exercise-induced plasma SPX in rats.
• Further research is needed to fully understand the systemic spexin response to exercise and its secretion sites.