| Keywords |
Treadmill training ; SCI ; BDNF ; Proliferation of astrocyte ; Gridwalk |
| Abstract |
Physical activity and exercise can improve sensorimotor recovery after central nerve injury. Among neurotrophic factors, brain-derived neurotrophic factor (BDNF) is known to modulate several neuronal functions including cell survival. Yet, a correlation between the induction of these proteins in non-neuronal cells and functional recovery is largely unknown. Seven-week-old male Sprague-Dawley rats were divided into three groups to know the effects of treadmill exercise on BDNF expression and functional recovery after spinal cord contusion in the rats; normal(intact)group(N=15), SCI(sedentary)group(N=15), and SCI+TMTgroup(N=15). Training group(TMT) is exercised on a treadmill maintained by a 30-min run at 0o inclination five times for a week during seven weeks one week after SCI. Here, we report that the low-intensity treadmill training (TMT) in rats upregulates BDNF protein levels in nonneuronal cells in the injured spinal cord and further facilitates axonal regrowth. Western blot analyses showed that levels of BDNF were increased in injury site 8 weeks after spinal cord contusion, and further upregulated by TMT. Enhancement of these protein in each region after TMT in contused rats was associated with proliferation of astrocytes by 8 weeks post injury. The extent of axonal sprouting in the injury site regions was higher in TMT group than sedentary group. Gridwalk tests were used to evaluate behavioral improvement after spinal cord contusion. All behavioral scales were improved in TMT group compared with sedentary group. Thus, the present data provide a new evidence that increased BDNF activity in proliferating astrocytes after spinal cord injury may play an important role in TMT-mediated enhancement of functional recovery in the injured central nerve. |