Long-term postmortem survival of mitochondrial genomes in mouse synaptosomes and their rescue in a mitochondrial DNA-less mouse cell line.

Mitochondrial DNA (mtDNA) transfer was carried out from postmortem mouse tissues to mouse mtDNA-less (rho0) cells to determine how long it takes for autolysis of mtDNA after death and whether mtDNA in postmortem tissues can recover its function in rho0 cells. The results showed that mtDNA was stable in postmitotic tissues stored at 4 degreesC. Moreover, mtDNA in postmortem brain tissues stored for up to 1 month still retained functional properties, causing complete recovery of mitochondrial respiratory function, when it was transferred to rho0 cells. These observations suggest that mtDNA in brain tissue can survive for 1 month after death and can start replication and gene expression in rho0 cells without showing any functional defects. This procedure might be applied to human autopsy brain tissues for examination of the influence of accumulated somatic mutations in mtDNA from aged subjects.