延髓头端腹内侧区在紫杉醇诱导的大鼠神经病理性痛中的作用研究

Research on the effects of rostral ventromedial medulla in paclitaxel induced neuropathic pain in rats

目的研究延髓头端腹内侧区立体定位注射局部麻醉药罗哌卡因对紫杉醇诱导的大鼠神经病理性痛的影响,探讨紫杉醇诱导的神经病理性痛的机制。方法建立紫杉醇诱导的大鼠神经病理性痛模型,在立体定位仪引导下于大鼠延髓头端腹内侧区(rostral ventromedial medulla,RVM)置管,检测RVM区给予罗哌卡因前后模型大鼠机械性痛觉超敏和热痛觉过敏的改变。结果构建紫杉醇诱导的大鼠神经病理性痛模型后,机械性痛觉超敏和热痛觉过敏痛阈进行性下降(P<0.05)。RVM区注射罗哌卡因后,模型大鼠的机械性痛觉超敏和热痛觉过敏痛阈升高(P<0.05),疼痛缓解。结论紫杉醇诱导的神经病理性痛大鼠RVM区注射局部麻醉药罗哌卡因后可显著缓解疼痛,说明RVM区在紫杉醇诱导的神经病理性痛发病机制中起重要作用。

[Objective] To study the effects and mechanisms of stereotactic intra rostral ventromedial medulla （RVM） injection of local anesthetic ropivacaine in paelitaxel induced neuropathic pain rats. [Methods] After the rat model of paclitaxeI induced neuropathie pain was established, the RVM cannulation was made on a rat stereotactie apparatus. Mechanical allodynia and thermal hyperalgesia were determined before and after intra RVM injection of ropivacaine in paclitaxel induced neuropathic pain rats. [Results] After the establishment of rat model of paelitaxel induced neuropathic pain, the threshold of mechanical allodynia and thermal hyperalgesia progressively decreased （P 〈0.05）. The threshold of mechanical allodynia and thermal hy- peralgesia were increased significantly （P〈0.05） and the pain behaviors were attenuated in paclitaxel induced neuropathie pain rats following intra RVM injection of ropivacaine. [ Conclusions ] The pathologic pain of paelitaxel induced neuropathic pain rats was significantly reversed after intra RVM injection of ropivacaine, suggesting that RVM plays a crucial role in the pathogenesis of paelitaxel induced neuropathic pain.