Mitochondrial complex I inhibition in cerebral cortex of immature rats following homocysteic acid-induced seizures.
Level 5 - mechanism / opinion, no new human data
Preclinical animal laboratory experiment (CEBM Level 5).
PubMed 17270175 · doi:10.1016/j.expneurol.2006.12.010
What was done
Immature rats received bilateral intracerebroventricular infusions of dl-homocysteic acid (HCA, 600 nmol/side) to induce seizures. Researchers measured mitochondrial respiratory chain enzyme activities (complexes I, II, IV, and citrate synthase), complex I protein content, oxidative stress markers (lipoperoxidation, aconitase activity, reactive oxygen species production), mitochondrial respiration, and cortical ATP levels during the acute phase of seizures (60–90 min post-infusion) and 20 hours post-seizure. The effects of anticonvulsants and free radical scavengers on complex I activity were also tested.
What was found
The abstract reports directional findings without numerical values, error metrics, or statistical significance levels: - Complex I activity decreased markedly at 60–90 minutes post-infusion and remained reduced for at least 20 hours. - The inhibition was selective for complex I; complex I protein content and activities of complexes II, IV, and citrate synthase were unaffected. - Lipoperoxidation and reactive oxygen species generation increased, while aconitase activity decreased. - Mitochondrial respiration and cortical ATP levels remained in the control range. - Anticonvulsant treatments and free radical scavengers substantially attenuated the complex I inhibition.
Why it matters
This study provides mechanistic evidence in a developmental seizure model that seizure-induced oxidative modification selectively impairs mitochondrial complex I, highlighting potential pathways for antioxidant neuroprotective strategies.
Limits
The study was conducted in a chemically induced animal model (immature rats), precluding direct translation to human clinical epilepsy. The abstract reports no sample sizes (n), quantitative values, or variance metrics. Neurofunctional and histological outcomes beyond 20 hours were not assessed.
Cited by
- supports Elevated homocysteine is metabolized into homocysteic acid, which acts as a mitochondrial toxin.