Research On The Rehabilitative Effects Of Robotic Assisted Body-weight-support Treadmill Training Starting At Different Time Points For Spinal Cord Injury

Exercise training is an effective,economic and sustainable rehabilitation method for SCI,and early initiation of exercise training can improve the rehabilitation effects of SCI greatly.However,the optimal assistance pattern for paralyzed limbs and the best starting time point for exercise training in the early phase of SCI are still inconclusive.Based on the above issues,two parts of animal experiments were carried out in this study:I.Establishment and evaluation of the Normal Rat Step PatternOBJECTIVES:1.To establish Normal Rat Step Pattern(NRSP)based on Rodent Robotic Motor Performance System(RRMPS),which conforms to the normal gait characteristics of rats.2.To screen out the better assistance pattern for paralyzed limbs rehabilitation in the early phase of SCI,by comparing the differences in rehabilitation effects of body-weight-support treadmill training(BWSTT)between NRSP assistance and manual assistance(MA).METHODS:1.Method for experimental animal grouping:40 male Wistar rats,8 of which were used for recording NRSP.The other 32 were randomly divided into 4 groups(n=8/group),including Sham group(only accepted laminectomy),Sedentary group(SCI),NRSPA group(SCI),MA group(SCI).2.Method for NRSP establishment:The hind limbs’gait information of normal rats was recorded using RRMPS robotic arm.The recorded gait information was analyzed,edited and combined by gait analysis software to form a 30-second NRSP,and the stability and consistency of NRSP were verified.3.Method for rehabilitation effects comparison between NRSP and MA:The rats in NRSPA group and MA group started 3w BWSTT at 3d after SCI.The hind limbs of NRSPA group were assisted by NRSP,and the hind limbs of MA group were assisted by MA.After training,the rehabilitation effects of the two groups were compared from three aspects:motor function(BBB score,RRMPS gait analysis),spinal nerve function(tceMEPs)and spinal cord nerve regeneration(NF200 positive expression at spinal cord lesion centre).RESULTS:1.Successful establishment of NRSPThe variation coefficient of the gait parameters of each single step in the 30s NRSP was less than 15%,and the differences in the gait parameters between the left and right limbs were not statistically significant(P>0.05).2.Rehabilitation effects comparison of motor function between NRSPA group and MA groupThere was no difference in BBB scores between the two groups after 1st BWSTT(P>0.05).The BBB scores were significantly higher in the NRSPA group after 2nd and 3rd week BWSTT than the MA group(P<0.001).The results of RRMPS gait analysis showed that the step length(P<0.05),step height(P<0.01)and effective step numbers in 30s(P<0.05)were significantly better in the NRSPA group than the MA group.3.Rehabilitation effects comparison of spinal cord nerve function between NRSPA group and MA groupThe latencies of tceMEPs in NRSPA group were significantly shorter than those of MA group(P<0.05),and the amplitudes of tceMEPs in NRSPA group were significantly higher than those in MA group(P<0.05).4.Comparison of spinal nerve regeneration between NRSPA group and MA groupNF200~+MFI values were significantly higher in NRSPA group than MA group(P<0.05);NF200~+AF values were no significant difference between MA group and NRSPA group(P>0.05).CONCLUSIONS:1.The established NRSP based on robotic arms had the characteristics of high stability and consistency and conformed to the normal gait characteristics of rats.It can be used as an effective robotic assisted pattern for paralyzed limbs of SCI rats during BWSTT.2.The rehabilitation effects of NRSP assistance was better than that of manual assistance(MA)based on BWSTT.II.Rehabilitation effects of body-weight-support treadmill training starting atdifferent time points for Spinal cord injuryOBJECTIVES:To determine the optimal starting time point for BWSTT in the early phase of SCI,by comparing the differences in rehabilitation effects between groups of SCI rats which started BWSTT at different time points within one month after SCI.METHODS:1.Method for experimental animal grouping60 male Wistar rats were randomly divided into 6 groups(n=10/group),including Sham group,Sedentary group,BWSTT-A group,BWSTT-B group,BWSTT-C group and BWSTT-D group.2.Method for rehabilitation effects comparison between groups starting BWSTT at different time pointsRats in BWSTT-A group,BWSTT-B group,BWSTT-C group and BWSTT-D group started 3w BWSTT at 3d,7d,14 d,and 21d after SCI respectively.The NRSP performed by robotic arms was used for paralyzed hind limbs assistance.The rehabilitation effects of all experimental groups were compared from four aspects:motor function(BBB score),spinal cord nerve function(tceMEPs),spinal cord nerve regeneration(NF200~+expression at spinal cord lesion centre)and BDNF and GAP-43 protein expression levels in the spinal cord.RESULTS:1.Rehabilitation effects comparison of motor function between groupsBBB scores of rats in all BWSTT groups showed a trend of increasing first and a slight falling down latter,and the changing curves of BBB scores for each BWSTT group showed significant differences.In the course of the experiment,rats in BWSTT-C group obtained the highest peak value of BBB score among all BWSTT groups.At the end of the experiment,BBB scores in BWSTT-C groups were significantly higher than BWSTT-A group(P<0.05)and BWSTT-B group(P<0.05),and BWSTT-D group,but the difference of BBB score between BWSTT-C group and BWSTT-D Group was not statistically significant(P>0.05).2.Rehabilitation effects comparison of spinal cord nerve function between groupsThe tceMEPs of all SCI rats showed a trend of latency shortening and amplitude increasing.But the changing curves of the latencies and amplitudes in all BWSTT groups were significantly different.At the end of the experiment,the latencies of tceMEPs in the BWSTT-C group were significantly shorter than those of BWSTT-A(P<0.01),BWSTT-B group(P<0.05)and BWSTT-D group(P<0.01);the amplitudes of tceMEPs in BWSTT-C group were significantly higher than those in BWSTT-A group(P<0.001)and BWSTT-B group(P<0.001).However,there was no difference on amplitudes between BWSTT-C group and BWSTT-D group(P>0.05).3.Comparison of spinal nerve regeneration between groupsThe NF200~+MFI values of BWSTT-C group were significantly higher than those of BWSTT-A(P<0.001)and BWSTT-B group(P<0.05),but there was no difference in NF200~+MFI values between BWSTT-D group and BWSTT-C group(P>0.05).NF200~+AF values of BWSTT-C group were significantly higher than those in BWSTT-A group(P<0.01),BWSTT-B group(P<0.05)and BWSTT-D group(P<0.05).4.Comparison of BDNF and GAP-43 protein expression in spinal cord between groupsThe expression of BDNF protein in the spinal cord of BWSTT-D group was significantly higher than that in other BWSTT groups(P<0.001).The expression of GAP-43 protein in the spinal cord of BWSTT-C group was significantly higher than that in other BWSTT groups(P<0.001).CONCLUSIONS:The rats starting BWSTT as 14 days after SCI obtained the best motor function recovery,spinal nerve function rehabilitation,spinal cord nerve regeneration and GAP-43 protein expression in spinal cord.Therefore,based on SCI rats,it was considered that 14 days after SCI was the optimal starting time point for BWSTT.