慢性坐骨神经结扎大鼠前扣带皮层对脊髓痛觉信息传递的调节

Anterior cingulated cortex modulating the nociception of spinal in CCI rats

目的本研究观察慢性坐骨神经结扎(CCI)大鼠前扣带皮层(ACC)对脊髓痛觉信息传递的调节。方法成年雄性SD大鼠32只,随机分为四组:Sham组,假手术组,仅分离出坐骨神经;CCI组,右侧坐骨神经结扎组;ACC组,正常大鼠,双侧ACC定点注射生理盐水1μl/侧;AP-5组,CCI术后13d,双侧ACC定点注射NMDA受体拮抗剂AP-5 25mM,1μl/侧。明暗箱实验、强迫游泳实验、机械痛阈、热痛阈等行为学测试完成后,将大鼠麻醉,取ACC和腰膨大脊髓,用Western blot方法检测磷酸化环磷腺苷效应元件结合蛋白(pCREB)和磷酸化细胞外调节蛋白激酶(pERK)的表达。结果与Sham组比较,CCI组术后2周机械痛阈值明显下降,明箱内时间明显缩短,穿梭次数明显减少,游泳潜伏期明显延长,手术侧脊髓pERK和pCREB的表达明显增多,ACC内pERK和pCREB的表达明显增多(P均<0.01)。与CCI组比较,AP-5组术后2周机械痛阈明显升高,热痛阈明显升高,大鼠在明箱内时间明显延长,穿梭次数明显增多,且游泳潜伏期明显缩短,手术侧脊髓pERK和pCREB表达明显减少(P均<0.01)。结论 ACC参与了CCI大鼠脊髓痛觉信息传递的调节。

Objective To observe how the ACC transmits nociceptive information and how it regulates spinal noceciption.Methods A total of 32 male SD rats were randomly divided into four groups：Sham group,CCI group,ACC group,and AP-5group.After light-dark transition test,forced swimming test（FST）,paw withdrawal mechanical threshold（PWMT）,paw withdrawal thermal latency（PWTL）had been measured,the rats were finally anesthetized,then ACC and the spinal cord was rapidly removed,the expression of cAMP-response element binding protein（pCREB）and extracellular regulated protein kinases（pERK）were measured by Western blot.Results Compared with the sham group,the PWMT of the CCI rats were significantly decreased,rats spent less time in the light compartment and number of transition were decreased（P〈0.01）.The immobility time in FST were also significantly prolonged（P〈0.01）.After AP-5injected in bilateral ACC 13 days after CCI operation,the PWMT of the CCI rats were significantly increased,rats spent more time in the light compartment and number of transition were increased（P〈0.01）.The immobility time in FST were also significantly shortened（P〈0.01）.Compared with sham group,the expression of pCREB,pERK increased significantly in ACC in CCI group（P〈0.01）.The expression of pCREB,pERK in spinal cord was increased in CCI group and decreased in AP-5group（P〈0.01）.Conclusion ACC facilitate the spinal nociception in a descending mode.