Free radical-dependent changes in constitutive Nuclear factor kappa B in the aged hippocampus.

We have examined the levels of constitutively active NF-kappaB subunits p65, p50 and p52 in the hippocampus of aged (24 months) young (3 months) F344 rats. Although we found no significant age-dependent difference in baseline nuclear levels of any subunit, we did note a differential response to treatment with the antioxidant PBN. While PBN significantly reduced nuclear levels of all three subunits in aged rats, only p50 was significantly reduced in the nuclei of young animals. This shows that the impetus for constitutive NF-kappaB activity is different in young and aged animals and may reflect a state of chronic oxidative stress in the latter. In addition this suggests a dysregulation of NF-kappaB and may contribute to the inability of the aged CNS to cope with insults such as trauma and ischemia/reperfusion.