Aims: 

In the present study we aimed at comparing the effects of long-term physical exercise and 17b-estradiol treatment in late adult and aged rats on cognitive functions and the relevant intracellular molecular signaling pathways in the hippocampus. It was assumed that both treadmill exercise and estradiol treatment activate similar neuroprotective pathways and support mitochondrial function.

Methods: 

The following cognitive behavioral tests were applied: novel object recognition, Y-maze, and Morris water maze spatial learning tests. The biochemical markers were assayed by Western blot: BDNF, p-MAPK, p-CREB, synapsin I, synaptophysin. The amount of reactive oxygen species (ROS) and carbonylated proteins were also measured.

Results: 

Results showed that both kind of treatments improved learning and memory functions of late adult rats. Like 17b-estradiol, physical training enhanced the level of BDNF resulting in the activation of MAPK/CREB pathway. The treatments also enhanced the density of synaptic molecules, which could underlay the improved cognitive functions. In addition, the level of ROS and the amount of carbonylated proteins decreased significantly in the hippocampus in response to the treatments. Similar tendencies were observed in aged animals, but the changes were training intensity-dependent.

Conclusion: 

Both exercise and estradiol treatment can produce rather comparable neuro- and psychotrophic effects, not only on the late adult but also on the aging brain, which indicates that similar cellular signaling mechanisms should be operated. These presently unraveled common signaling pathways at the end increase transcription factor p-CREB.