The ketogenic diet increases mitochondrial glutathione levels

J Neurochem. 2008 Aug;106(3):1044-51. doi: 10.1111/j.1471-4159.2008.05460.x. Epub 2008 May 5.

Abstract

The ketogenic diet (KD) is a high-fat, low carbohydrate diet that is used as a therapy for intractable epilepsy. However, the mechanism(s) by which the KD achieves neuroprotection and/or seizure control are not yet known. We sought to determine whether the KD improves mitochondrial redox status. Adolescent Sprague-Dawley rats (P28) were fed a KD or control diet for 3 weeks and ketosis was confirmed by plasma levels of beta-hydroxybutyrate (BHB). KD-fed rats showed a twofold increase in hippocampal mitochondrial GSH and GSH/GSSG ratios compared with control diet-fed rats. To determine whether elevated mitochondrial GSH was associated with increased de novo synthesis, the enzymatic activity of glutamate cysteine ligase (GCL) (the rate-limiting enzyme in GSH biosynthesis) and protein levels of the catalytic (GCLC) and modulatory (GCLM) subunits of GCL were analyzed. Increased GCL activity was observed in KD-fed rats, as well as up-regulated protein levels of GCL subunits. Reduced CoA (CoASH), an indicator of mitochondrial redox status, and lipoic acid, a thiol antioxidant, were also significantly increased in the hippocampus of KD-fed rats compared with controls. As GSH is a major mitochondrial antioxidant that protects mitochondrial DNA (mtDNA) against oxidative damage, we measured mitochondrial H2O2 production and H2O2-induced mtDNA damage. Isolated hippocampal mitochondria from KD-fed rats showed functional consequences consistent with the improvement of mitochondrial redox status i.e. decreased H2O2 production and mtDNA damage. Together, the results demonstrate that the KD up-regulates GSH biosynthesis, enhances mitochondrial antioxidant status, and protects mtDNA from oxidant-induced damage.

Publication types

  • Comparative Study

MeSH terms

  • Animals
  • Antioxidants / metabolism
  • Blood Glucose / metabolism
  • Food, Formulated*
  • Glutathione / metabolism*
  • Ketone Bodies / administration & dosage*
  • Male
  • Mitochondria / metabolism*
  • Rats
  • Reactive Oxygen Species / metabolism

Substances

  • Antioxidants
  • Blood Glucose
  • Ketone Bodies
  • Reactive Oxygen Species
  • Glutathione