Voluntary exercise increases the new cell formation in the hippocampus of ovariectomized mice.

Voluntary exercise, such as running, can induce dramatic increases in adult hippocampal neurogenesis and improve learning and memory function. A recent report showed that exercise also improved memory problems in postmenopausal women. In this study, we examined whether voluntary running exercise could increase new cell formation in the hippocampus under menopausal conditions, modeled with ovariectomized (OVX) mice. Voluntary running exercise for 1 week significantly increased the number of bromodeoxyuridine (BrdU)- and Ki-67-immunoreactive cells in the hippocampus of mice 2 weeks after ovariectomy. In addition, 1 week of voluntary running exercise after 2 weeks in OVX mice increased the numbers of doublecortin- and calretinin-immunoreactive cells in the hippocampus. These data demonstrate that exercise may increase the birth of new cells in the hippocampus under estrogen-deprived conditions, suggesting that exercise may be helpful in improving brain function in climacteric women.