Treadmill exercise improves short-term memory by suppressing ischemia-induced apoptosis of neuronal cells in gerbils

In the present study, the effect of treadmill exercise on short-term memory, apoptotic neuronal cell death, and cell proliferation in the hippocampal dentate gyrus following transient global ischemia in gerbils was investigated. Step-down inhibitory avoidance task, terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) assay, and immunohistochemistry for caspase-3 and 5-bromo-2'-deoxyuridine (BrdU) were used. Ischemia was induced by the occlusion of both common carotid arteries (CCA) of gerbils for 5 min. Gerbils in exercise groups were forced to run on a treadmill for 30 min once a day for 10 consecutive days. Such treadmill exercise improved short-term memory by suppressing the ischemia-induced apoptotic neuronal cell death in the dentate gyrus. In addition, treadmill running suppressed the ischemia-induced cell proliferation in the dentate gyrus. The present results suggest that treadmill exercise overcomes the ischemia-induced apoptotic neuronal cell death and thus facilitates the recovery following ischemic cerebral injury.