title: Exercise promotes motor functional recovery in rats with corticospinal tract injury: anti-apoptosis mechanism.
abstract: Studies have shown that exercise interventions can improve functional recovery after spinal cord injury, but the mechanism of action remains unclear. To investigate the mechanism, we established a unilateral corticospinal tract injury model in rats by pyramidotomy, and used a single pellet reaching task and horizontal ladder walking task as exercise interventions postoperatively. Functional recovery of forelimbs and forepaws in the rat models was noticeably enhanced after the exercises. Furthermore, TUNEL staining revealed significantly fewer apoptotic cells in the spinal cord of exercised rats, and western blot analysis showed that spinal cord expression of the apoptosis-related protein caspase-3 was significantly lower, and the expression of Bcl-2 was significantly higher, while the expression of Bax was not signifiantly changed after exercise, compared with the non-exercised group. Expression of these proteins decreased with time after injury, towards the levels observed in sham-operated rats, however at 4 weeks postoperatively, caspase-3 expression remained significantly greater than in sham-operated rats. The present findings indicate that a reduction in apoptosis is one of the mechanisms underlying the improvement of functional recovery by exercise interventions after corticospinal tract injury.
authors.affiliation: Department of Orthopedics, China-Japan Union Hospital of Jilin University, Changchun, Jilin Province, China.
authors.forename: Ting-Ting
authors.initials: TT
authors.lastname: Hou
authors.affiliation: Department of Orthopedics, China-Japan Union Hospital of Jilin University, Changchun, Jilin Province, China.
authors.forename: Xiao-Yu
authors.initials: XY
authors.lastname: Yang
authors.affiliation: Department of Orthopedics, China-Japan Union Hospital of Jilin University, Changchun, Jilin Province, China.
authors.forename: Peng
authors.initials: P
authors.lastname: Xia
authors.affiliation: Department of Orthopedics, China-Japan Union Hospital of Jilin University, Changchun, Jilin Province, China.
authors.forename: Su
authors.initials: S
authors.lastname: Pan
authors.affiliation: Department of Orthopedics, First Clinical Medical College of Three Gorges University, Yichang, Hubei Province, China.
authors.forename: Jian
authors.initials: J
authors.lastname: Liu
authors.affiliation: Department of Orthopedics, China-Japan Union Hospital of Jilin University, Changchun, Jilin Province, China.
authors.forename: Zhi-Ping
authors.initials: ZP
authors.lastname: Qi
keywords: Bax; Bcl-2; NSFC grants; apoptosis; caspase-3; corticospinal tract; exercise; functional recovery; nerve regeneration; neural regeneration; spinal cord injury