炎性痛大鼠背根节及脊髓后角NMDAR1与BSI-B4免疫荧光双标记观察及针刺调节

A FLUORESCENT DOUBLE LABELED OBSERVATION OF NMDAR1 AND BSI-B4 IN THE SPINAL DORSAL HORN OF THE INFLAMMATION-INDUCED RAT AND ITS ELECTROACUPUNCTURE MODULATION

目的 探讨在伤害性刺激条件下 ,初级感觉传入C纤维中枢突末梢上的NMDA受体NR1亚型蛋白(NMDAR1,NR1)的变化。 方法 对单侧佐剂性关节炎性痛模型 ,采用西非单叶豆同工凝集素 (BSI B4 )与NR1免疫荧光双标技术 ,观察致炎后不同时间段初级感觉传入突触前NR1的表达及其针刺后的变化。 结果 分别在各组大鼠的背根节和脊髓观察到BSI B4 NR1的双标产物。致炎后第 3d、7d各组大鼠致炎侧背根节中的双标神经元占各单标神经元的百分比关系为 :炎症组 (包括 3d、7d组 ) >电针组 (包括 3d、7d组 ) >生理盐水组 (包括 3d、7d组 ) (P <0 0 1) ;且炎症组和电针组大鼠均表现为 3d组 >7d组 (P <0 0 1)。 结论 提示脊髓后角突触前C纤维中枢突末梢上存在NR1,而且参与了单侧佐剂性关节炎大鼠痛觉过敏的形成 ;电针可能通过下调突触前的NR1抑制中枢敏化的形成 ,达到治疗的目的。

Objective Glutamate, acting at a spinal N-methyl-D-aspartate(NMDA) receptor has been implicated in development of central sensitization. The goal of the present study was to provide morphological evidences for the relation of NR1 to primary afferent C fiber in the spinal dorsal horn of the rat following inflammatory pain. Methods The Sprague-Dawley rats were divided into control group(n=12), inflammation group(n=12) and electroacupuncture(EA) treatment group(n=12). EA was done in acuponints “Huan Tiao”(GB30) and “Yang Lin Quan” (GB34) (stimulation indices: 0.5-1.5V, 4-16Hz, 30min ) following injection of Complete Freund’s adjuvant(CFA). Using immunofluoresence histochemical double-staining technique, we examined the distributions and relationships between Banderaea Simplicifolia Isolectin B4(BSI-B4) labeled primary afferent C fibers and terminals and NR1 in the dorsal root ganglion(DRG) and superficial laminae of the spinal dorsal horn following CFA-induced inflammation and EA treatment. Results NR1 was located in primary afferent C fibers and terminals of both DRG and superficial laminae of the spinal dorsal horn. In addition, we also found in the DRG that, at 3rd d and 7th d following injection of CFA, the percentages of the number of double-labeled cells to the total number of the BSI-B4 labeled cells and NR1 immunoreactive cells, respectively, all showed that: inflammation group>EA treatment group> control group(P<0.01), and 3rd group>7th group(P<0.05). Conclusion NR1 was located in primary afferent C fibers and terminals, and the up-regulation and activation of this presynaptic NR1 may contribute significantly to the hyperalgesia that accompanies persistent inflammation. Moreover, EA treatment could down-regulate the NR1 expression following inflammation to analgesia consequently.