电针对坐骨神经分支选择性损伤大鼠痛觉过敏及脊髓NOS活性、NO水平的影响

The role of electroacupuncture on hyperalgia and NOS activity as well as NO concentration within the spinal cord of rats with spared nerve injury

目的探讨电针对神经病理性痛大鼠痛觉过敏以及脊髓一氧化氮合酶（NOS）活性和一氧化氮（NO）水平的影响。方法40只SD大鼠，随机分为空白组、假手术组、手术组和电针组（n=10）。采用坐骨神经分支选择性损伤模型，电针“委中”和“环跳”穴，观察其对大鼠机械痛阈和热痛阈的影响，以分光光度法测定脊髓总NOS以及nNOS、iNOS活性和NO水平。结果坐骨神经分支选择性损伤术可明显降低大鼠机械痛阈，手术组10d时为（14．83±0．79）g，与空白组和假手术组相比，差异有显著性（P〈0．05）；并且手术组脊髓总NOS和nNOS活性以及NO水平均明显升高，分别为（44．23±7．81）U／mgprot和（39．64±10．28）U／mgprot以及（112．79±18．01）μmol／g，与空白组和假手术组相比，均差异有显著性（P〈0．01），iNOS却有降低的趋势；而电针干预后大鼠脊髓总NOS和nNOS活性明显降低，分别为（32．14±12．05）U／mgprot和（20．97±12．16）U／mgprot，NO合成也明显减少，为（70．96±18．15）μmol／g，与手术组各项比较差异有显著性（P〈0．05，P〈0．01）；与此同时显著减轻坐骨神经分支选择性损伤大鼠的机械痛敏状态，进而改善其痛行为。结论电针减轻神经病理性痛可能与其抑制脊髓NOS活性、降低NO水平有关。

Objective To investigate the effect of electroaoupuncturc （EA） on hyperalgcsia, and NOS activity and NO concentration within the spinal cord of rats with spared nerve injury （SNI）. Methods Forty adult SD rats were randomly divided into a control （ C ） group, a sham-operation （ SO ） group and an operation （ O ） group. A spared nerve injury （SNI） model was established by ligating and severing the common peroneal nerve and the proso-tibial nerve under anesthesia. The rats within the O group were randomly divided into a model （M） subgroup,and an electroacupuncture （E） subgroup. The success of the SNI operation was measured by determi- ning the mechanical pain thresholds of each rat. In the E subgroup EA （2Hz, onset l mA, enhance 1 mA each 10 rain） was applied to ＂Wei zhong＂ （BL 40） and ＂Huan tiao＂ （GB 30） for 30 minutes. Total NOS,nNOS,and iNOS activity as well as the concentration of NO were then measured by absorption spectrometry. Results After the SNI operation the mechanical pain threshold for the O group at day 10 （ 14.83 ± 0.79g） was significantly lower then that of groups C and SO （P 〈 0. 11 and P 〈 0.05 respectively）. In addition, total NOS [ （44.23 ±7.81 ） U/ mgprot ] and nNOS [ （39.64 ± 10.28） U/mgprot ] activity as well as NO concentration [ （ 112.79 ± 18.01 ） μmol/ g] of the O group within the spinal cord were significantly （P〈0.01） higher than those of the C and SM groups, whereas iNOS activity was markedly reduced. After acupuncture the total NOS [ （32.14 ± 12.05 ） U/mgprot, P 〈 0.05 ] and nNOS [ （20.97 ± 12. 16 ）U/mgprot, P 〈 0. 01 ] activity, as well as NO concentration [ （70.96 ± 18.15 ）μmol/g] within the spinal cord for the E subgroup was significantly reduced in comparison to that of the M subgroup; simultaneously, the mechanical pain thresholds of the E group heightened significantly compared to that of the M group. Conclusion It is suggested that EA analgesic mechanism may be related to the reduction of hyperalgesia,as well a decrease in NOS activity and NO concentration within the spinal cord in SNI.