Mechanical ventilation induces diaphragmatic mitochondrial dysfunction and increased oxidant production

Area of Science:

• Physiology
• Biochemistry
• Cellular Biology

Background:

• Mechanical ventilation (MV) is crucial for acute respiratory failure but can cause diaphragmatic weakness, hindering weaning.
• Reactive oxygen species (ROS) are implicated in MV-induced diaphragmatic weakness, but the underlying pathways are unclear.
• Mitochondria are a potential source of ROS, but their role in MV-induced diaphragmatic dysfunction requires investigation.

Purpose of the Study:

• To test the hypothesis that prolonged MV increases mitochondrial ROS release, oxidative damage, and dysfunction in the diaphragm.
• To investigate the impact of MV on mitochondrial respiratory function and electron transport chain activity.

Main Methods:

• Adult female Sprague-Dawley rats were subjected to 12 hours of MV or served as controls.
• Diaphragms were harvested, and mitochondria were isolated for respiratory and biochemical analyses.
• Measurements included respiratory control ratio, ROS release, lipid peroxidation, protein oxidation, and electron transport chain complex activities.

Main Results:

• MV led to a lower respiratory control ratio in diaphragmatic mitochondria.
• Mitochondria from MV animals exhibited increased ROS release during respiration.
• MV was associated with increased mitochondrial oxidative damage (lipid peroxidation, protein oxidation) and depressed electron transport chain complex activities (II, III, IV).

Conclusions:

• Prolonged MV promotes increased mitochondrial ROS emission, oxidative damage, and respiratory dysfunction in the diaphragm.
• These mitochondrial alterations likely contribute to diaphragmatic weakness and impaired weaning from mechanical ventilation.
• Targeting mitochondrial ROS production may offer therapeutic strategies to mitigate MV-induced diaphragmatic dysfunction.