Protective effects of treadmill exercise on apoptotic neuronal damage and astrocyte activation in ovariectomized...

Both estrogen deprivation and diabetes mellitus are known as risk factors for neuronal damage. Using an animal model of ovariectomized and/or streptozotocin (STZ)-induced diabetes mellitus, we examined expression of apoptosis-related proteins, neuronal damage, and astrocyte activation in prefrontal cortex of rats with/without treadmill exercise.

Adult female Wistar rats were divided into control, ovariectomized (Ovx, bilateral ovariectomy), diabetic (Dia, STZ 60 mg/kg; i.p.), and ovariectomized diabetic (Ovx + Dia) groups. Next, animals in each group were randomly subdivided into non-exercise and exercise subgroups. Animals in the exercise groups underwent moderate treadmill running for 4 weeks (5 days/week). Thereafter, expression of Bax, Bcl-2, and caspase-3, as apoptosis-related proteins, number of neurons, and number of glial fibrillary acidic protein (GFAP)-positive cells in prefrontal cortex were measured using immunoblotting, cresyl violet staining, and immunohistochemistry, respectively.

In both Dia and Ovx + Dia groups, Bax and caspase-3 protein levels and number of GFAP-positive cells were higher than those in the control group, while Bcl-2 protein level and number of neurons compared were lower than the control group. Beneficial effects of exercise to prevent apoptosis-mediated neuronal damage and astrocyte activation were also observed in the Dia group.

Based on our results, physical exercise could be beneficial to attenuate diabetes-induced neuronal damage in the prefrontal cortex via inhibition of apoptosis.