鞘内注射昂丹司琼对神经病理性疼痛大鼠的影响

Effect of intrathecal injection of ondansetron on chronic neuropathic pain in rats

目的观察鞘内注射5-HT3受体拮抗剂昂丹司琼对大鼠神经病理性疼痛行为及脊髓背角5-HT3受体表达的影响。方法采用大鼠坐骨神经结扎制作慢性神经病理性疼痛模型。坐骨神经结扎7 d后,采用热缩足反射潜伏期和机械缩足反射阈值方法检测大鼠鞘内注射昂丹司琼前后痛觉阈值的变化。然后处死大鼠,用免疫组织化学染色法和Western blot方法检测大鼠鞘内注射昂丹司琼前后脊髓背角5-HT3受体的表达变化。结果鞘内给药前,模型组大鼠的痛觉阈值低于正常组(P<0.05),脊髓背角5-HT3受体表达明显高于正常组(P<0.05);鞘内给药后,5μg和10μg昂丹司琼能提高模型组大鼠痛觉阈值,且大鼠脊髓背角5-HT3受体表达明显减少(P>0.05)。结论鞘内注射昂丹司琼抑制脊髓5-HT3受体的表达后可以减轻大鼠慢性神经病理性疼痛。

【Objective】To investigate the effect of intrathecal injection of 5-HT3 receptor antagonist ondansetron on pain behavior and 5-HT3 receptors expression in spinal cord following chronic neuropathic pain in rats.【Methods】Chronic neuropathic pain model was established from sciatic nerve ligation. After model replication in the 7th day, thermal withdrawal latency（TWL） and mechanical withdrawal threshold（MWT） were used to detect the pain threshold before and after intrathecal injection of ondansetron in rats. Immunohistochemical staining and western blotting were used to detect the expression of the spinal 5-HT3 receptors before and after intrathecal injection of ondansetron in rats. 【Results】Before intrathecal injection of ondansetron： the pain threshold by TWL and MWT in model rats were lower than that of control rats（P 0.05）; the expression of 5-HT3 receptors in the spinal cord in model rats was higher than that of control rats（P 0.05）. After intrathecal injection of ondansetron： the dose of 5 μg and 10 μg ondansetron could improve the pain threthold in model rats, and also could reduce the expression of 5-HT3 receptors in the spinal cord in model rats（P 0.05）. 【Conclusion】Blockade the spinal 5-HT3 receptors by intrathecal injection of ondansetron could attenuate the chronic neuropathic pain.