Denervation-induced skeletal muscle atrophy is associated with increased mitochondrial ROS production

Area of Science:

• Muscle biology
• Mitochondrial function
• Neurodegenerative diseases

Background:

• Reactive oxygen species (ROS), particularly mitochondrial ROS, are implicated in muscle atrophy.
• Aging, genetic mutations (Sod1(-/-)), and amyotrophic lateral sclerosis (ALS) are associated with muscle atrophy and increased ROS.

Purpose of the Study:

• To investigate the correlation between mitochondrial ROS generation and muscle atrophy in various models.
• To determine the role of denervation in mitochondrial ROS production during muscle atrophy.

Main Methods:

• Assessed mitochondrial ROS generation in muscle mitochondria from aging mice, Sod1(-/-) mice, and two ALS mouse models (G93A and H46RH48Q).
• Quantified muscle mass loss in these models.
• Investigated mitochondrial ROS production in hindlimb muscles following surgical sciatic nerve transection (denervation).

Main Results:

• Mitochondrial ROS production significantly increased in aging, Sod1(-/-), and ALS mouse models, correlating with muscle mass loss.
• Aging mice showed a threefold increase in ROS and 30% muscle loss.
• Sod1(-/-) mice exhibited over 100% ROS increase and >50% muscle loss.
• ALS models showed substantial ROS increases (4- to 12-fold) and 30-75% muscle loss.
• Denervation led to a nearly 30-fold increase in mitochondrial ROS production within seven days.

Conclusions:

• Enhanced mitochondrial ROS generation is strongly correlated with the extent of muscle atrophy across different models.
• Denervation-induced muscle atrophy is associated with a significant increase in mitochondrial ROS production.
• Elevated mitochondrial ROS may be a common mechanistic factor in denervation-induced muscle atrophy.