Proton Magnetic Resonance Spectroscopy (H1-MRS) Study of the Ketogenic Diet on Repetitive Mild Traumatic Brain Injury in Adolescent Rats and Its Effect on Neurodegeneration.

OBJECTIVE: A ketogenic diet (KD) improves cellular metabolism and functional recovery after moderate-to-severe traumatic brain injury. Here, we evaluated the changes of neurochemical metabolites after KD therapy for repetitive mild traumatic brain injury (rmTBI) and its possible role in neurodegeneration. METHODS: Postnatal day 35 rats were randomly divided into 3 groups: sham, control, and KD groups. Rats in control and KD groups were given 3 rmTBI by a fluid percussion traumatic brain injury device 24 hours apart. All rats were killed at 7 days after the last injury. The ipsilateral cortex were analyzed with hematoxylin and eosin staining; beta-hydroxybutyrate was measured; conventional magnetic resonance imaging and the dry-wet weight method were used to assess the brain edema; changes of neurochemical metabolites were assessed using the ratio of N-acetylaspartate (NAA)/creatine (Cr), choline compound (Cho)/Cr, and NAA/Cho with magnetic resonance spectroscopy; the effect of KD therapy on neurodegeneration was evaluated with double immunofluorescence staining of Iba-1/beclin-1; behavioral outcome was assessed with beam walk/beam balance tests. RESULTS: KD significantly elevated beta-hydroxybutyrate levels, and there was no brain edema associated with rmTBI and KD therapy; behavioral assessment showed KD therapy significantly improved motor performance; magnetic resonance spectroscopy showed that rmTBI reduced the ratio of NAA/Cr and had no effect on the ratios of Cho/Cr and NAA/Cho whereas KD increased the ratio of NAA/Cr; double immunofluorescence staining showed KD therapy could significantly decrease microglial beclin-1 expression in the ipsilateral cortex. CONCLUSIONS: These results suggest the effect of KD on metabolic status and its possible role in preventing neurodegeneration in adolescent rats after rmTBI.

The protective effect of the ketogenic diet on traumatic brain injury-induced cell death in juvenile rats.

BACKGROUND: The ketogenic diet (the KD) is an effective treatment for intractable epilepsy, especially in the paediatric population, and a growing number of studies have shown the neuroprotective role of the KD. However, few studies focused on the neuroprotective effects of the KD in traumatic brain injury (TBI). The present study aimed to investigate the effects of the KD on TBI. METHODS AND PROCEDURES: Male Sprague-Dawley rats (n = 60) were randomly divided into four groups according to the diet fed (the KD vs normal diet) and whether brain was injured or not. TBI was produced using Feeney weight drop model. Brain oedema was estimated by wet/dry weight ratio; Bax and Bcl-2 mRNA levels were determined by RealTime-PCR; Bax and Bcl-2 protein levels were detected by Western blot. Furthermore, cellular apoptosis in the penumbra area was examined using terminal deoxynucleotidyl transferase-mediated dUTP nick end labelling (TUNEL) method. MAIN OUTCOMES AND RESULTS: The results indicated that both Bax mRNA and protein levels were significantly elevated 72 hours after TBI and decreased by KD administration. Neither TBI nor the KD affected Bcl-2 mRNA and protein levels. KD administration also reduced brain oedema and cellular apoptosis. CONCLUSION: These results suggest that the KD might be a useful treatment for children suffering from the consequences of TBI.

Compression-induced brain edema in rats: effect of dietary vitamin E on membrane damage in the brain.

Vasogenic edema was produced by focal epidural brain compression followed by sudden decompression in rats raised on diets that varied in content of vitamin E. Cerebral content of total fatty acids and vitamin E was assayed at 24 hours postdecompression after a 24-hour period of compression. Levels of all individual fatty acids in the previously compressed brain region were less by 19 to 22% in the vitamin E-deficient group than in sham-operated controls (p less than 0.05); by 4 to 13% in the vitamin E-normal group; and by 0 to 7% in the vitamin E-supplemented group. Brain levels of vitamin E were not altered by compression in any group. By physicochemical interaction with phospholipids, vitamin E may serve to stabilize membranes after this type of brain injury.

Compression-induced brain edema: modification by prior depletion and supplementation of vitamin E.

We studied the degree of edema resulting from focal brain compression in rats raised on vitamin E-deficient, -normal, or -supplemented diets. After release of 24 hours of epidural compression, edema developed ipsilaterally and was characterized by extravasation of serum protein, increased water and sodium content, and little change in potassium. The degree of swelling and increase of sodium in the previously compressed area were most pronounced in the vitamin E-deficient group and mildest in the vitamin E-supplemented group. Degradative processes of biomembranes seem to participate in the pathogenesis of brain edema; vitamin E may stabilize membranes by physicochemical interactions between the phytyl side chain and polyunsaturated phospholipids, or vitamin E may disrupt chains of free radical reactions.