Effects of Exercise on Expressions of Brain-Derived Neurotrophic Factor and Tyrosine Kinase Receptor B in Injured Spinal Cord of Rats / 天津医药

ABSTRACT

Objective To investigate the effects of exercise on expressions of brain-derived neurotrophic factor (BDNF) and tyrosine kinase receptor B (TrkB) in spinal cord of spinal cord injury (SCI) rats. Methods Spinal cord injury models were produced by universal spinal cord impact system. Twenty-four Sprague-Dawley rats were randomly divided into 3 groups, exercise group (SCI-induction and exercises, n=8), control group (SCI-induction without exercises,n=8) and sham-operation group (no operation, without SCI nor exercises, n=8). Exercise training began from the 7th day after injury for 4 weeks. The locomotor function was assessed by Basso-Beattic-Bresnahan (BBB) scale before injury and at the 1st, 2nd, 3rd, 4th and 5th week post injury. The expressions level of BDNF and TrkB in spinal cords were detected by immunohistochemis-try and Western blot. Results Since the 3rd week after injury (after 2 weeks of exercise training), BBB scores in exercise group were higher than that in control group (P ＜ 0.05). In immunohistochemistry test, positive immunologic reaction to BDNF protein was mainly located in anterior horn of spinal cord, and the expression level in exercise group was significantly higher than that in sham-operation group and control group (P＜0.05). In immunohistochemistry test, positive immunologic reaction to TrkB protein was located in anterior horn and dorsal horn and central canal of spinal cord, and the expression lev-el in exercise group was significantly higher than that in sham-operation group and control group (P＜0.05). Expression of BDNF and TrkB in exercise group rats after exercise for 4 weeks were significantly increased, compared with that in control group. Conclusion Exercise training may effectively induce BDNF and TrkB expression in spinal cords and promote the re-covery of locomotor function of SCI rats.