ABSTRACT
OBJECTIVE: To observe the changes of intracellular calcium ([Ca2＋]i) concentration and expression of calcium/calmodulin dependent protein kinaseⅡ (CaMKⅡ) in spinal dorsal horn neurons of spared nerve injury (SNI) rats, so as to explore its mechanisms underlying improvement of neuropathic pain. METHODS: One hundred and ten SD rats were randomly divided into 5 groups: sham control, model, EA, AP-5 and L-NAME groups. The sham group underwent only a simple separation of the sciatic nerve but without ligation and abscission. The neuropathic pain model was established by abscission of the right tibial and common peroneal nerve. EA (2 Hz, 1－3 mA) was applied to right "Weizhong" (BL 40) and "Huantiao" (GB 30) for 30 min, once a day for 7 days, starting from day 11 after surgery. For rats of the AP-5 and L-NAME groups, AP-5 (a competitive antagonist for NMDA receptor, 0.7 mg·kg－1·d－1) and L-NAME (a non-selective antagonist for nitric oxide synthase [NOS], 60 mg·kg－1·d－1) were respectively administrated by intraperitoneal injection, once daily for 7 days. The mechanical pain threshold was measured, and the calcium fluorescence intensity (shown by Fluo-3/AM calcium fluorescence indicator) of the superficial layer of the lumbar spinal cord (L 4－L 6) was measured by immunohistochemical staining and the expression of spinal cord (L 4－L 6) CaMK Ⅱ protein was detected by Western blot (WB). RESULTS: After modeling, the mechanical pain threshold was significantly decreased on day 10 and 16 after operation in comparison with the sham operation group and baseline data of pre-operation in each group (P<0.01), and remarkably increased in the EA, AP-5 and L-NAME groups relevant to the model group on day 16 (P<0.01, P<0.05), while the effect of EA was significantly superior to that of AP-5 and L-NAME groups (P<0.05), suggesting a reduction of EA analgesia after administration of AP-5 and L-NAME. The concentration of intracellular [Ca2＋]i was significantly higher in the model group than in the sham group, and considerably lower in the EA, AP-5 and L-NAME groups than in the model group (P<0.01, P<0.05). Moreover, the expression level of CaMKⅡ shown by WB and immunohistochemical staining was significantly higher in the model group than in the sham group (P<0.05) and obviously lower in the EA group (not the AP-5 and L-NAME groups) than in the model group on day 16 after the intervention (P<0.05). It suggests an involvement of glutamate NMDA receptor and NMDAR-NOS/NO signaling in the analgesic effect and CaMKⅡ expression down-regulation of EA. CONCLUSIONS: EA can ease pain in rats with neuropathic pain, which is closely related to its effect in reducing the calcium concentration and the expression of CaMKⅡ in the lumbar spinal cord, possibly mediated by glutamate NMDA receptor and NMDAR-NOS/NO signaling.
ABSTRACT
<p><b>OBJECTIVE</b>To observe the clinical efficacy on primary trigeminal neuralgia treated with joint needling method at the trigger point.</p><p><b>METHODS</b>One hundred and three cases of primary trigeminal neuralgia were divided into a joint needling group (53 cases) and a conventional needling group (50 cases) according to the visit sequence. In the joint needling group, the joint needling method was used at the trigger point in the mandibular joint [the positive point near to Xiaguan (ST 7)]; the conventional needling was used at Hegu (LI 4), Waiguan (TE 5), Taichong (LR 3) and Neiting (ST 44). In the conventional needling group, Xiaguan (ST 7) and Fengchi (GB 20) were used and the supplementary acupoints were selected according to the involved branches of trigeminal nerve. The conventional needling method was used. The Visual Analogue Scale (VAS) and the score of trigeminal neuralgia were adopted to assess the pain severity and the comprehensive symptoms before treatment and after the 1st and 2nd sessions of treatment separately. The efficacy was assessed.</p><p><b>RESULTS</b>After the 1st and 2nd sessions of treatment, VAS score and the comprehensive symptom score were reduced obviously as compared with those before treatment in either group (P < 0.05, P < 0.01). The score reducing in the joint needling group was much superior to that in the conventional needling group (both P < 0.05). The total effective rate was 90.6% (48/53) and 72. 0% (36/50) in the joint needling group and the conventional needling group respectively. The effect in the joint needling group was better than that in the conventional needling group (P < 0.05).</p><p><b>CONCLUSION</b>The joint needling method at the trigger point achieves the significant efficacy on primary trigeminal neuralgia, which is superior to that with the conventional needling method.</p>