Electroacupuncture improves gait locomotion, H-reflex and ventral root potentials of spinal compression injured rats.

This study explored the effect of electroacupuncture stimulation (EA) on alterations in the Hoffman reflex(H-reflex) response and gait locomotion provoked by spinal cord injury (SCI) in the rat. A compressionlesion of the spinal cord was evoked by insufflating a Fogarty balloon located in the epidural space atthe T8-T9 spinal level of adult Wistar male rats (200-250 gr; n = 60). In different groups of SCI rats, EA(frequencies: 2, 50 and 100 Hz) was applied simultaneously to Huantiao (GB30), Yinmen (BL37), Jizhong (GV6) and Zhiyang (GV9) acupoints from the third post-injury day until the experimental session. At 1,2, 3 and 4 post-injury weeks, the BBB scores of the SCI group of rats treated with EA at 50 Hz showed agradual but greater enhancement of locomotor activity than the other groups of rats. Unrestrained gaitkinematic analysis of SCI rats treated with EA?50 Hz stimulation showed a significant improvement instride duration, length and speed (p < 0.05), whereas a discrete recovery of gait locomotion was observedin the other groups of animals. After four post-injury weeks, the H-reflex amplitude and H-reflex/Mwave amplitude ratio obtained in SCI rats had a noticeable enhancement (217%) compared to sham rats(n = 10). Meanwhile, SCI rats treated with EA at 50 Hz manifested a decreased facilitation of the H-reflexamplitude and H/M amplitude ratio (154%) and a reduced frequency-dependent amplitude depression ofthe H-reflex (66%). In addition, 50 Hz-EA treatment induced a recovery of the presynaptic depression ofthe Gs-VRP evoked by PBSt conditioning stimulation in the SCI rat (63.2 8.1%; n = 9). In concordance withthe latter, it could be suggested that 50 Hz-EA stimulation reduced the hyper-excitability of motoneuronsand provokes a partial improvement of the locomotive performance and H reflex responses by a possiblerecovery of presynaptic mechanisms in the spinal cord of experimentally injured rats.