Neurons in the cerebral cortex are most susceptible to DNA-damage in aging rat brain

Using nick translation type of incubation and terminal deoxynucleotidyl transferase catalyzed 3 -end labeling, single and double strand breaks in genomic DNA of permeabilised neurons from different regions of young, adult and the aged rat brain were assessed. A steady increase in both types of breaks is noted with advancement of age in all of the brain regions studied. However, the number of SSB encountered in the cerebral cortex was the maximum and was also markedly higher than that in other brain regions. When the neuronal cells were exposed to MNNG or Glutamate the damage was aggravated in all the regions and at all ages but the most severe SSB damage is present in the cerebral cortex of older animals. Both cerebral cortex and the hippocampus showed equally higher DSB in comparison with the other regions. It is concluded that with advancement of age, DNA-damage accumulates in neurons and the cerebral cortex is the most vulnerable region.