Modulation of the hippocampal protein machinery in voluntary and treadmill exercising rats

Information about protein expression studies in the brain of exercising and sedentary animals is limited. Cognitive functions change during exercise and the aim of this study was to investigate rat protein levels of the protein machinery in the hippocampus, the main cognitive brain area for spatial learning and memory, in exercising rats. Protein fluctuations may reflect functional variation during exercise. Male Sprague-Dawley rats, 23 months old, were used for the study: the first group consisted of sedentary rats, the second of rats undertaking voluntary exercise from 5 months to 23 months and the third undertaking involuntary exercise on a treadmill from 5 months to 23 months. Two-dimensional gel electrophoresis with subsequent mass spectrometrical identification assigning spots to proteins and determination of coomassie-densities was carried out. Heterogeneous nuclear ribonucleoprotein K, one protein variant of heat shock cognate 71 kDa protein and BAG family molecular chaperone regulator 5 showed differential protein levels in the three groups when a p-value of <0.005 was considered as statistically significant thus respecting multiple testing. The biological meaning of changed protein levels in hippocampus under different conditions of exercise is not known but warrants further investigation.