推拿对神经病理性疼痛大鼠内侧前额叶皮质突触可塑性的影响OA

Objective To observe the effects of massage on synaptic plasticity of medial prefrontal cortex(mPFC)in rats with neuropathic pain;To explore its mechanism of central analgesia.Methods Totally 36 SD rats were randomly divided into blank group,model group and massage group(n=12).A chronic compression injury of sciatic nerve model was established to simulate neuropathic pain.Starting from the 4th day after modeling,the massage group received massage intervention(5 N,120 times/min,10 min/day)for 14 consecutive days,while the blank group and model group received no intervention.The mechanical paw withdrawal threshold(PWT)and thermal paw withdrawal latency(PWL)of affected hind limb were measured before modeling and on days 4,10,14,and 17 after modeling.After the intervention,the left mPFC tissue was collected,synaptic structures were observed by transmission electron microscopy,the location and expression of NMDA receptor(NR)2B were analyzed by immunohistochemistry,the protein expression of NR2B,calcium/calmodulin-dependent protein kinase(CaMK)Ⅱ,postsynaptic density protein(PSD)-95 and synapsin(SYP)in mPFC were detected by Western blot.Results Compared with the blank group,PWT and PWL in the model group rats significantly decreased(P<0.001),the number of synapses in mPFC neurons decreased,the synaptic space widened,the PSD became thinner,the synaptic active band shortened,and the curvature of synaptic interface decreased(P<0.05),the positive expression of NR2B in mPFC tissue increased significantly(P<0.001),the protein expressions of NR2B and CaMKⅡ increased significantly(P<0.001),and the protein expressions of PSD-95 and SYP decreased significantly(P<0.001).Compared with the model group,PWT and PWL in the massage group significantly increased(P<0.001),the number of synapses in mPFC neurons increased,the synaptic space narrowed,the PSD thickened,the synaptic active band elongated,and the curvature of synaptic interface increased(P<0.05),the positive expression of NR2B in mPFC significantly decreased(P<0.01),the protein expressions of NR2B and CaMKⅡ significantly decreased(P<0.05),and the protein expressions of PSD-95 and SYP significantly increased(P<0.05).Conclusion Massage can effectively relieve neuropathic pain in rats with chronic compression injury of sciatic nerve.The underlying central analgesic mechanism may involve the bidirectional regulation of synaptic protein expression in mPFC,namely by down-regulating the overactivated NR2B/CaMKⅡsignaling pathway to inhibit neuronal hyperexcitability,and up-regulating PSD-95 and SYP to promote synaptic reconstruction and functional optimization,thereby restoring the mPFC management of descending pain pathways.