The Study On Mechanism Of Neuroplasticity And Expression Of Serotonin And GABA Induced By Epidural Spinal Cord Stimulation And Partial Weightbearing Treadmill Therapy After Spinal Cord Injury

Objective： To observe locomotion recovery induced by epidural spinal cordstimulation combined with partial weightbearing treadmill after complete spinal cordinjury (SCI) in rats, and to explore the mechanism of the epidural spinal cordstimulation (ESCS) combined with partial weightbearing treadmill (PWBT) therapy. Itwill provide evidences for clinical treatment parameters, and theoretical basis forscientific research.Methods： Thirty adult male Sprague-Dawley rats, weighting250-280g, wererandomly divided into five groups: normal control group (group A), SCI group (groupB), SCI+PWBT group (group C), SCI+ESCS group (group D), SCI+ESCS+PWBTgroup (group E), with6cases in every group. T8spinal cord transection was uesed forcomplete SCI models, and two electrodes were implanted underneath the T13and L1vertebral bodies for ESCS preparations. Treatments were carried out after two weekssince the operation. The function of locomotion and residual urine volume wereevaluated, and immunohistochemical technique was involved to assess the expression ofsynapsinⅠ(SynⅠ), serotonin (5-HT), serotonin transporter (SERT), serotonin2A receptor (5-HT2AR) and glutamate decarboxylase67(GAD67) in lumbar spinal cord.Results：①In the ESCS combined with PWBT group, locomotor function scoresincreased significantly at6th week compared with SCI group (P＜0.05), while PWBTalone or ESCS alone significantly improved BBB scale at the7th week (P＜0.05). At8th week after surgery, Syn Ⅰ in PWBT, ESCS and ESCS+PWBT group increasedsignificantly compared with SCI group. Residual urine volume in D group was less,however, there was no significant difference with other groups (P＞0.05).②Compared with normal control group,5-HT and SERT in SCI group decreased (P＜0.05), and ESCS+PWBT improved their expressions（P＜0.05）. The expression of5-HT2AR in PWBT, ESCS and ESCS+PWBT group increased significantly than SCIgroup. Compared with normal control group, GAD67in SCI group increasedsignificantly (P＜0.05), and the ESCS combined with PWBT treatment decreased itsexpression (P＜0.05).Conclusion：Locomotion capacity after complete spinal cord injury can be improvedby ESCS combined with PWBT. The expression of neuroplastcity in lumbar spinal cordis in consistent with the improvements of locomotion. The ESCS combined with PWBTtraining may activate spinal CPG, which is modulated by various neurotransmitters,such as serotonin, GABA. This combined therapy is able to enhance the activation ofCPG with serotonin up regulation, and reduce the inhibition of CPG with GABA downregulation. These changes make CPG generate motor patterns, and improve locomotion.