Objective To assess the effect of electrical stimulation and weight-supported treadmill gait simulation on apoptosis in the muscles of rats with spinal cord injury.
Method Twenty seven rats with a model of complete spinal cord injury were assigned to one of the following groups: control (n=9), electrical stimulation (n=10), and exercise (n=8) groups. After a 2-week intervention period, they were sacrificed, and the pattern of apoptosis was analyzed by in situ DNA nick-end labeling (TUNEL), by DNA fragmentation assay, and by Western blot for Bax and Bcl-2 using specimens from the right hamstring muscles for all groups.
Results The electrical stimulation group had increased apoptosis compared to the control group possibly due to overwork weakness, but there was no statistical significance between the groups. Apoptosis decreased in the exercise group compared with in the electrical stimulation and control group. The expression of Bcl-2 was most prominent in the exercise group, and it was significantly reduced in the electrical stimulation and control group.
Conclusion These findings suggest that exercise could play an important role in decreasing apoptosis by the up-regulation of Bcl-2 protein expression and that electrical stimulation might cause overwork weakness in rat models of spinal cord injury.
