Effects of botulinum toxin combined with treadmill training on motor and gastrocnemius function after spinal cord injury / 中华物理医学与康复杂志

ABSTRACT

Objective To observe the effects of botulinum toxin A(BTX-A) injection combined with treadmill training on motor and gastrocnemius function in rats after spinal cord injury (SCI),so as to develop a possible treatment.Methods A total of 48 female Sprague-Dawley rats were randomly divided into four groups(n =12 in each)a control group which received normal saline injection(group Con-NS),an exercise group with normal saline injection(group Ex-NS),the other control group with BTX-A injection(group Con-BTX)and an exercise group which also received BTX-A injection(group Ex-BTX).All rats were subjected to incomplete SCI modelling using Allen's method.Each group then had l0 members left because of death or significant weight loss.After SCI modelling,BTX-A or normal saline were injected to rats' gastrocnemius,followed by weight support treadmill training(BWSTT) on days 7 through 35 days for the two exercise groups.Motor function was evaluated using inclined plane test before and 2 days,1,2,3,4 and 5 weeks after the injury.All rats were sacrificed 35 days after the surgery.Digit Abduction Scoring(DAS) and electrophysiological testing were performed prior to sacrifice,and the general form and the wet weight of gastrocnemius were observed after resection.Results No significant differences in the inclined plane angle among 4 groups were detected before injury and 2 days afterward (P ＞ 0.05).At the 2nd-Sth week,however,the inclined plane angles in group Ex-NS were significantly higher than those in group Con-NS (P ＜ 0.05).Those of group Ex-NS were also significantly higher than group Ex-BTX 2-5 weeks after injury (P ＜ 0.05).No significant differences were detected between group Con-BTX and group Ex-BTX,as well as group Con-NS and group Ex-BTX at each time point (P ＞ 0.05).And the average DAS score in group Con-BTX and group Ex-BTX was 0,while that of Con-NS group and group Ex-NS were both 4.There were no significant differences between the two normal saline injection groups (P ＜ 0.05),nor between the two BTX-A injection groups (P ＜ 0.05).However,the average DAS scores in the Con-BTX and Ex-BTX groups were significantly higher than the Con-NS and Ex-NS groups (P ＜ 0.05).No significant atrophy of gastrocnemius muscles were observed in the Con-NS group or Ex-NS group,and as would be expected,the muscles in group Ex-NS were thicker on average than those in group Con-NS.Significant atrophy was observed in group Con-BTX and group Ex-BTX.Moreover,the muscle wet weight was significantly higher in group ExNS than group Con-NS (P ＜ 0.05).Compared with group Con-NS and group Ex-NS,the muscle wet weight was significantly lower in group Con-BTX and group Ex-BTX (P ＜ 0.05).No significant differences in the latency of the compound muscle action potential (CAMP) were detected among 4 groups (P ＞0.05),but the CAMP amplitude was significantly less in the control groups than in the exercise groups.(P ＜0.05).Conclusions Exercise training can significantly improve motor and skeletal muscle function in SCI rats,but BTX-A injection can inhibit the improvement.