Mitochondrial DNA Deletion in the Cerebral Cortex, Hippocampus and Cerebellum of the Aged Rats

Objective By measuring the ratio of mtDNA deletion of brain tissue, the relationship between mtDNA deletion and brain aging would be found in order to explain the molecular mechanism of aging. Method The mtDNA of the cerebral cortex, hippocampus and cerebellum of ten young (3 months) and seventeen aged (24 months) SD rats were isolated by alkaline extraction. The ratio of mtDNA deletion was measured by serial dilution PCR. Result The 4 834 bp deletion in mtDNA was found in the brain tissue of young and aged rats. The ratios of deleted mtDNA were similar in the cerebral cortex, hippocampus, cerebellum of young rats (0 000 156%,0 000 148%,0 000 152%). The ratios of aged rats increased by 9,10 and 6 5 fold in the three brain regions over young rats. Conclusions mtDNA deletion also accumulated in the aged rat brain. It suggests that the accumulation of deleted mtDNA may be one of important factors of neuronal degeneration with aging.