Tuina therapy promotes behavioral improvement and brain plasticity in rats with peripheral nerve injury and repair.

INTRODUCTION: Tuina is currently one of the popular complementary and alternative methods of rehabilitation therapy. Tuina can improve patients' pain and mobility function. However, the underlying physiological mechanism remains largely unknown, which might limit its further popularization in clinical practice. The aim of this study is to explore the short-term and long-term changes in brain functional activity following Tuina intervention for peripheral nerve injury repair. METHODS: A total of 16 rats were equally divided into the intervention group and the control group. Rats in the intervention group received Tuina therapy applying on the gastrocnemius muscle of the right side for 4 months following sciatic nerve transection and immediate repair, while the control group received nerve transection and repair only. The block-design functional magnetic resonance imaging scan was applied in both groups at 1 and 4 months after the surgery. During the scan, both the injured and intact hindpaw was electrically stimulated according to a "boxcar" paradigm. RESULTS: When stimulating the intact hindpaw, the intervention group exhibited significantly lower activation in the somatosensory area, limbic/paralimbic areas, pain-regulation areas, and basal ganglia compared to the control group, with only the prefrontal area showing higher activation. After 4 months of sciatic nerve injury, the control group exhibited decreased motor cortex activity compared to the activity observed at 1 month, and the intervention group demonstrated stronger bilateral motor cortex activity compared to the control group. CONCLUSION: Tuina therapy on the gastrocnemius muscle of rats with sciatic nerve injury can effectively alleviate pain and maintain the motor function of the affected limb. In addition, Tuina therapy reduced the activation level of pain-related brain regions and inhibited the decreased activity of the motor cortex caused by nerve injury, reflecting the impact of peripheral stimulation on brain plasticity.

Brain plasticity after peripheral nerve injury treatment with massage therapy based on resting-state functional magnetic resonance imaging.

Massage therapy is an alternative treatment for chronic pain that is potentially related to brain plasticity. However, the underlying mechanism remains unclear. We established a peripheral nerve injury model in rats by unilateral sciatic nerve transection and direct anastomosis. The experimental rats were treated over the gastrocnemius muscle of the affected hindlimb with a customized massage instrument (0.45 N, 120 times/min, 10 minutes daily, for 4 successive weeks). Resting-state functional magnetic resonance imaging revealed that compared with control rats, the amplitude of low-frequency fluctuations in the sensorimotor cortex contralateral to the affected limb was significantly lower after sciatic nerve transection. However, amplitudes were significantly higher in the massage group than in a sham-massage group. These findings suggest that massage therapy facilitated adaptive change in the somatosensory cortex that led to the recovery of peripheral nerve injury and repair. This study was approved by the Animal Ethics Committee of Shanghai University of Traditional Chinese Medicine of China (approval No. 201701001) on January 12, 2017.

Cortical remodeling after electroacupuncture therapy in peripheral nerve repairing model.

Electroacupuncture (EA) is an alternative therapy for peripheral nerve injury (PNI). The treatment relies on post-therapeutic effect rather than real-time effect. We utilized fMRI to clarify the resting-state alteration caused by sustained effect of EA on peripheral nerve repairing model. Twenty-four rats were divided equally into three groups: normal group, model group and intervention group. Rats of the model and intervention group underwent sciatic nerve transection and direct anastomosis. EA intervention at ST-36 and GB-30 was conducted continuously for 4 months on the intervention group. Behavioral assessments and fMRI were performed 1 month and 4 months after surgery. Intervention group showed significant improvement on the gait parameters max contact mean intensity (MCMI) and thermal withdrawal latency (TWL) than model group. EA-related sustained effects of amplitude of low frequency fluctuations (ALFF) could be described as a remolding pattern of somatosensory area and sensorimotor integration regions which presented higher ALFF in the contralateral hemisphere and lower in the ipsilateral hemisphere than model group. Interhemispheric functional connectivity (FC) analysis showed a significantly lower FC after EA therapy between the largest significantly different clusters in bilateral somatosensory cortices than the model group 4 months after surgery(p < 0.05). And the model group presented significantly higher FC than the normal group at both two time-points (p < 0.01). The sustained effect of EA on peripheral nerve repairing rats appeared to induce both regional and extensive neuroplasticity in bilateral hemispheres. We proposed that such EA-related effect was a reverse of maladaptive plasticity caused by PNI.

A Longitudinal Mapping Study on Cortical Plasticity of Peripheral Nerve Injury Treated by Direct Anastomosis and Electroacupuncture in Rats.

OBJECTIVE: We used functional magnetic resonance imaging to provide a longitudinal description of cortical plasticity caused by electroacupuncture (EA) of sciatic nerve transection and direct anastomosis in rats. METHODS: Sixteen rats in a sciatic nerve transection and direct anastomosis model were randomly divided into intervention and control groups. EA intervention in the position of ST-36, GB-30 was conducted continuously for 4 months in the intervention group. Functional magnetic resonance imaging and gait assessment were performed every month after intervention. RESULTS: The somatosensory area was more activated in the first 2 months and then deactivated in the rest 2 months when EA was applied. The pain-related areas had the same activation pattern as the somatosensory area. The limbic/paralimbic areas fluctuated more during the EA intervention, which was not constantly activated or deactivated as previous studies reported. We attributed such changes in somatosensory and pain-related areas to the gradual reduction of sensory afferentation. The alterations in limbic/paralimbic system might be associated with the confrontation between the upregulating effect of paresthesia or pain and the downregulating effect of EA intervention through the autonomic nerve system. The gait analysis showed significantly higher maximum contact mean intensity in the intervention group. CONCLUSIONS: The alterations in the brain brought about by the long-term therapeutic effect of EA could be described as a synchronized activation pattern in the somatosensory and pain-related areas and a fluctuating pattern in the limbic/paralimbic system.