代谢型谷氨酸受体4通过Rab5抑制神经病理性痛

Suppressive effect of metabotropic glutamate receptor 4 on neuropathic pain by Rab5

目的探讨代谢型谷氨酸受体4（mGluR4）激活后抑制神经病理性痛的机制。方法首先取24只SD大鼠，鞘内置管后随机分为空白对照组（n=6）、假手术组（n=6）和脊神经根结扎（SNL）组（n=12）。空白对照组只行鞘内置管术，其余大鼠均于术前和术后第1～6日测量50％机械缩足阈值（50％PWT）；其次，将SNL组大鼠于术后第7日起，随机分为SNL＋生理盐水组（n=6）和SNL＋VU0155041组（n=6），分别予以鞘内注射生理盐水和VU0155041（500nm01）10μL，2次／d×7d，注药前和注药后30min测量其50％PWT。最后，末次给药后1h取空白对照组、SNL＋生理盐水组和SNL＋VU0155041组大鼠左侧脊髓腰膨大处送检基因芯片并利用Western blotting检测mGluR4及Rab5各亚型的表达变化。结果SNL大鼠术后1～6d其手术同侧后肢50％PwT较空白对照组及假手术组明显降低（P〈0．01）；SNL＋VU0155041组大鼠手术同侧后肢50％PwT与SNL＋生理盐水组相比自给药第4日起逐渐升高（P〈0．01）；Agilent表达谱基因芯片结果显示：SNL＋生理盐水组的Rab5含量高于空白对照组，而空白对照组和SNL＋VU0t55041组相比无明显差异；Western blotting结果显示：SNL＋生理盐水组的mGluR4表达明显低于空白对照组和SNL＋VU0155041组（P〈0．05），而Rab5A和Rab5C的表达明显高于空白对照组和SNL＋VU0155041组（P〈0．05），Rab5B在3组中的表达差异无统计学意义（P〉0．05）。结论mGluR4激活后可能是通过Rab5A和Rab5C调控突触囊泡递质释放从而影响神经病理性痛。

Objective To explore the mechanism of neuropathic pain suppression by activating metabotropic glutamate receptor 4 （mGluR4）. Methods Firstly, 24 SD rats were randomly divided into blank control group （n = 6）, shame operation group （ n = 6）, and SNL group （ n = 12） after intrathecal catheterization. Rats in control group were only undergone the intrathecal catheterization. Values of 50% PWT were measured for other rats before surgery and 1 - 6 d after surgery. Then, rats in SNL group were randomly divided into SNL ＋ saline group （n = 6） and SNL ＋ VU0155041 group （n =6） and received intrathecal injection of saline and VU0155041 （500 nmol） 10 μL twice a day for seven days, respectively. Values of 50% PWT were measured before injection and 30 min after injection. Finally, left spinal dorsal horn of the spinal enlargement of control group, SNL ＋ saline group and SNL ＋ VU0155041group were obtained lh after last injection and submitted for gene chip examination. The expression of mGluR4 and the subtypes of Rab5 were determined by Western blotting. Results During 1 - 6 d after surgery, values of 50% PWT of ipsilateral hindpaws in SNL group were significantly lower than those of the blank control group and shame operation group （P 〈 0. 01） ; the values of 50% PWT of the ipsilateral hindpaws in SNL ＋ VU0155041 group were gradually higher than those of SNL ＋ saline group from the forth day after injection （ P 〈0.01） ; and the results of Agilent gene chip showed that Rab5 in SNL ＋ saline group was higher than that of control group, while control group has no difference with SNL ＋ VU0155041 group. The expression of mGluR4 in SNL ＋ saline group was significantly lower than that of control group and SNL ＋ VU0155041 group （ P 〈 0.05）, but the expression of RabSA and Rab5C were significantly higher than those of control group and SNL ＋ VU0155041 group （P 〈 0. 05）,and the differences of activation of mGluR4 and Ran5C Rab5B expression among three groups were not statistically significant （P 〉0. 05）. Conclusion The can affect neuropathic pain by regulating neurotransmitter release of synaptic vesicles through Rab5A