Ageing introduces a complex pattern of changes in several rat brain transcription factors depending on gender and anatomical localization

As ageing changes the activity of several transcription factors in the rat cortex, we were interested in determining whether similar changes also appear in the hippocampus of old rats. We determined by electrophoretic gel shift assays the binding activity of nuclear factor kappa B (NFκB), activator protein-1 (AP-1), peroxisome proliferator-activated receptor (PPAR), and liver X receptor (LXR) in cortex and hippocampus samples from young (3-month-old), and old (18-month-old) male and female Sprague-Dawley rats. NFκB activity increased in old male and female rats, though only in cortex samples, while AP-1 activity decreased only in the cortex and hippocampus of old female animals. LXR activity decreased in all conditions, except in old male cortexes; whereas PPAR activity only decreased in the hippocampus of old female rats. Decreases in AP-1 and PPAR activities restricted to old female rats did not result from an age-related decline in plasma 17β-estradiol concentration, as their activities did not change in samples obtained from ovariectomized young female rats. Our results indicate that ageing induces a complex pattern of changes in the brain-binding activity of NFκB, AP-1, PPAR and LXR, depending on the anatomical origin of the samples (cortex or hippocampus), and the sex of the animals studied.