Rice bran extract protects from mitochondrial dysfunction in guinea pig brains

Area of Science:

• Neuroscience
• Mitochondrial Biology
• Nutraceutical Research

Background:

• Mitochondrial dysfunction is implicated in age-related neurodegenerative diseases.
• Food ingredients show potential for improving mitochondrial function.
• Stabilized rice bran extract (RBE) contains oryzanols, tocopherols, and tocotrienols, which may offer protective benefits.

Purpose of the Study:

• To investigate the effects of RBE on brain mitochondrial function in guinea pigs.
• To determine if RBE components like tocotrienols and CEHC accumulate in the brain.
• To assess RBE's impact on mitochondrial respiration, membrane potential, ATP levels, and biogenesis.

Main Methods:

• Guinea pigs were fed stabilized RBE.
• Mitochondrial function, including respiration and coupling, was assessed in isolated brain mitochondria.
• Mitochondrial membrane potential and ATP levels were measured in brain cells following sodium nitroprusside (SNP) challenge.
• Mitochondrial mass markers (citrate synthase, cardiolipin, respiratory chain complexes, TIMM) and fission proteins (Drp1, fis1) were quantified.

Main Results:

• RBE feeding significantly increased brain concentrations of α-tocotrienol and γ-carboxyethyl hydroxychroman (CEHC).
• Overall mitochondrial respiration and coupling were enhanced in RBE-fed animals.
• Brain cells from RBE-fed guinea pigs exhibited higher mitochondrial membrane potential and ATP levels post-SNP challenge.
• Increased mitochondrial mass and enhanced mitochondrial fission events (Drp1, fis1) were observed in RBE-fed guinea pigs.

Conclusions:

• RBE consumption improves mitochondrial function and enhances resistance to mitochondrial dysfunction in the brain.
• RBE increases mitochondrial mass and promotes mitochondrial fission, suggesting adaptive responses.
• RBE shows potential as a nutraceutical for preventing mitochondrial dysfunction and oxidative stress in brain aging and neurodegenerative diseases.