Dietary choline deprivation impairs rat brain mitochondrial function and behavioral phenotype

Area of Science:

• Neuroscience
• Biochemistry
• Nutritional Science

Background:

• Dietary choline deprivation (CD) is linked to behavioral changes, but the underlying mechanisms, particularly concerning brain mitochondrial function and cognition, remain unclear.
• Limited research exists on how CD impacts brain mitochondrial respiration, redox status, and associated cognitive impairments.

Purpose of the Study:

• To investigate the effects of 28-day dietary choline deprivation on brain mitochondrial function and redox status in male Wistar rats.
• To characterize the behavioral phenotype associated with choline deprivation, focusing on motor coordination, motor learning, and cognitive avoidance tasks.

Main Methods:

• Male Wistar rats were fed either a choline-deficient (CD) diet or a control (CTRL) diet for 28 days.
• Brain mitochondrial function was assessed by measuring respiration (state III and IV) and Complex I activity.
• Redox status was evaluated by measuring reactive oxygen species production, total glutathione, and protein oxidation. Mitochondrial cardiolipin levels were quantified.
• Behavioral tests included the rotarod/accelerod test for motor coordination and learning, and an active avoidance task to assess cognitive learning and memory.

Main Results:

• CD rats exhibited significantly lower NAD-dependent mitochondrial state III and state IV respiration compared to CTRL rats.
• Complex I activity was reduced by 40% in CD rats, accompanied by a significant increase in reactive oxygen species production.
• CD rats showed increased oxidative consumption of total glutathione and a 40% higher rate of protein oxidation, indicating oxidative stress.
• Mitochondrial cardiolipin concentration was 20% lower in CD rats, impacting Complex I function.
• Behaviorally, CD rats demonstrated impaired motor coordination and learning, and reduced capacity in active avoidance learning.

Conclusions:

• Dietary choline deprivation induces significant dysfunction in brain mitochondria, characterized by impaired respiration, reduced Complex I activity, and increased oxidative stress.
• These mitochondrial deficits correlate with observable impairments in motor coordination, motor learning, and cognitive avoidance tasks in CD rats.
• The findings highlight the critical role of adequate choline supply for maintaining brain mitochondrial integrity and cognitive function, similar to its known importance in the liver.