INSITU AUTOLYSIS OF MOUSE-BRAIN - ULTRASTRUCTURE OF MITOCHONDRIA AND THE FUNCTION OF OXIDATIVE-PHOSPHORYLATION AND MITOCHONDRIAL-DNA

The effect of in situ autolysis on cerebral mitochondrial structure an d function has been investigated. Mice (n = 9) were sacrified and stor ed for up to 24 h under unfavorable post-mortem conditions at 25-degre es-C. At different time intervals groups of three animals were submitt ed to post-mortem dissection and tissue from different regions of the brain was used for the preparation of ''free'' and synaptosomal mitoch ondria. On electron microscopic examination, the post-mortem period ha d no significant influence on mitochondrial morphology and enzymatic a ctivities of complexes I-V of the mitochondrial oxidative phosphorylat ion system were still present in all the mitochondrial preparations fr om different regions of the brain, albeit at a reduced levels. Degrada tion of mitochondrial DNA was virtually absent from mitochondrial prep arations during the 24-h period of autolysis, as shown by the presence of intact DNA by Southern blot and PCR analysis. Based on these resul ts, alterations in mitochondrial DNA and deficiencies of mitochondrial respiratory complexes I-V can be recognized in cerebral tissue even a fter 24 h of unfavorable post-mortem storage conditions.