Treadmill exercise increases cell proliferation without altering of apoptosis in dentate gyrus of Sprague-Dawley rats

The effects of forced treadmill exercise on cell proliferation and apoptosis in the hippocampal dentate gyrus in Sprague-Dawley rats were investigated. The animals were classified into three groups: the control group, the easy exercise group, and the moderate exercise group. In the control group, rats were left on the treadmill without running for 30 min per day, while rats in the exercise groups were made to run on the treadmill for the same duration. All rats were injected intraperitoneally with 5-bromo-2'-deoxyuridine (BrdU) one-hour prior to exercise once a day for 7 consecutive days beginning at the start of the exercise regimens. Each of the rats was sacrificed 2 h after the last exercise. Both the easy and moderate exercise groups revealed increased number of BrdU-positive cells in the dentate gyrus compared to the control group. The terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling (TUNEL) assay revealed very few apoptotic cells, with no statistically significant differences among the groups. These results showed that treadmill exercise increases cell proliferation without altering of apoptosis in the dentate gyrus of the hippocampus. (C) 2002 Elsevier Science Inc. All rights reserved.