Polysorbate 80-induced leaky gut impairs skeletal muscle metabolism in mice

Area of Science:

• Metabolic Physiology
• Gastroenterology
• Exercise Science

Background:

• Impaired intestinal permeability is linked to systemic inflammation and metabolic disorders.
• The specific impact of compromised gut barrier function on skeletal muscle metabolism remains unclear.
• Dietary polysorbate 80 (PS80), a common emulsifier, is known to disrupt intestinal permeability in animal models.

Purpose of the Study:

• To investigate the effects of PS80-induced intestinal permeability on glucose tolerance.
• To examine the impact on metabolic signaling pathways within skeletal muscle.
• To assess the consequences for muscle function, particularly after exercise.

Main Methods:

• Male ICR mice were administered PS80 in drinking water for 4 weeks.
• Intestinal permeability was assessed using fluorescein isothiocyanate (FITC)-dextran.
• Mice underwent running exercises, followed by analysis of blood and skeletal muscle for metabolic and inflammatory markers.

Main Results:

• PS80 ingestion increased plasma levels of FITC and lipopolysaccharide, indicating heightened intestinal permeability.
• Skeletal muscle showed increased tumor necrosis factor-α expression and impaired mitochondrial function (reduced pH, cytochrome oxidase activity, and post-exercise glycogen).
• Despite increased insulin resistance markers, direct insulin signaling in muscle was unaffected, but glucose intolerance and reduced exercise capacity were observed.

Conclusions:

• Daily intake of PS80 induces intestinal permeability, contributing to glucose intolerance.
• PS80 negatively affects skeletal muscle mitochondrial function and energy reserves.
• These findings highlight a link between dietary emulsifiers, gut health, and skeletal muscle metabolic disturbances.