Back to Search
Start Over
Temporal window of metabolic brain vulnerability to concussions: mitochondrial-related impairment--part I.
- Source :
-
Neurosurgery [Neurosurgery] 2007 Aug; Vol. 61 (2), pp. 379-88; discussion 388-9. - Publication Year :
- 2007
-
Abstract
- Objective: In the present study, we investigate the existence of a temporal window of brain vulnerability in rats undergoing repeat mild traumatic brain injury (mTBI) delivered at increasing time intervals.<br />Methods: Rats were subjected to two diffuse mTBIs (450 g/1 m height) with the second mTBI delivered after 1 (n = 6), 2 (n = 6), 3 (n = 6), 4 (n = 6), and 5 days (n = 6) and sacrificed 48 hours after the last impact. Sham-operated animals were used as controls (n = 6). Two further groups of six rats each received a second mTBI after 3 days and were sacrificed at 120 and 168 hours postinjury. Concentrations of adenine nucleotides, N-acetylated amino acids, oxypurines, nucleosides, free coenzyme A, acetyl CoA, and oxidized and reduced nicotinamide adenine dinucleotides, oxidized nicotinamide adenine dinucleotide phosphate, and reduced nicotinamide adenine dinucleotide, reduced nicotinamide adenine dinucleotide phosphate nicotinic coenzymes were measured in deproteinized cerebral tissue extracts (three right and three left hemispheres), whereas the gene expression of N-acetylaspartate acylase, the enzyme responsible for N-acetylaspartate (NAA) degradation, was evaluated in extracts of three left and three right hemispheres.<br />Results: A decrease of adenosine triphosphate, adenosine triphosphate/adenosine diphosphate ratio, NAA, N-acetylaspartylglutamate, oxidized and reduced nicotinamide adenine dinucleotide, reduced nicotinamide adenine dinucleotide, and acetyl CoA and increase of N-acetylaspartate acylase expression were related to the interval between impacts with maximal changes recorded when mTBIs were spaced by 3 days. In these animals, protracting the time of sacrifice after the second mTBI up to 1 week failed to show cerebral metabolic recovery, indicating that this type of damage is difficult to reverse. A metabolic pattern similar to controls was observed only in animals receiving mTBIs 5 days apart.<br />Conclusion: This study shows the existence of a temporal window of brain vulnerability after mTBI. A second concussive event falling within this time range had profound consequences on mitochondrial-related metabolism. Furthermore, because NAA recovery coincided with normalization of all other metabolites, it is conceivable to hypothesize that NAA measurement by 1H-NMR spectroscopy might be a valid tool in assessing full cerebral metabolic recovery in the clinical setting and with particular reference to sports medicine in establishing when to return mTBI-affected athletes to play. This study also shows, for the first time, the influence of TBI on acetyl-CoA, N-acetylaspartate acylase gene expression, and N-acetylaspartylglutamate, thus providing novel data on cerebral biochemical changes occurring in head injury.
- Subjects :
- Acetylation
Adenine Nucleotides metabolism
Amino Acids metabolism
Animals
Aspartic Acid analogs & derivatives
Aspartic Acid metabolism
Coenzymes metabolism
Disease Models, Animal
Glutamate Carboxypeptidase II genetics
Male
NADP metabolism
Nicotinic Acids metabolism
RNA, Messenger metabolism
Rats
Rats, Wistar
Recurrence
Severity of Illness Index
Time Factors
Brain metabolism
Brain Concussion metabolism
Energy Metabolism physiology
Mitochondria metabolism
Subjects
Details
- Language :
- English
- ISSN :
- 1524-4040
- Volume :
- 61
- Issue :
- 2
- Database :
- MEDLINE
- Journal :
- Neurosurgery
- Publication Type :
- Academic Journal
- Accession number :
- 17762751
- Full Text :
- https://doi.org/10.1227/01.NEU.0000280002.41696.D8