缺血性内脏痛模型大鼠脊髓背角NMDA受体NR2B亚单位的表达

The Expression of N-methy-D-aspartate NR2B receptor in spinal cord dorsal horn of rats′ visceral pain model induced by ischemia

目的探讨大鼠内脏缺血刺激后行为学反应及脊髓背角NMDA受体NR2B亚单位的表达变化。方法 36只SD大鼠随机分为假手术组(S组,n=18)和造模组(C组,n=18)。各组在手术后30、60、120、180min、第2d、第3d共6个时间段分别进行内脏疼痛强度的行为学评分。分别于术后3、7、14d随机取6只大鼠用免疫组织化学方法测定脊髓L4～5背角处的NMDA受体NR2B亚单位表达。结果造模组大鼠在结扎结肠系膜血管后60min均达到疼痛评分的最大值,与假手术组比较,造模组所有时间点疼痛行为评分明显升高(P<0.05);在脊髓L4～5节段NMDA受体NR2B亚单位的免疫阳性产物主要出现在背角深层和中央管周围。造模组大鼠3d的脊髓NMDA受体NR2B亚基的表达与假手术组差别无统计学意义(P>0.05);造模组大鼠7、14d的脊髓NMDA受体NR2B亚基的表达明显高于假手术组(P<0.05)。同组比较,7d组蛋白表达高于3d组和14d组(P均<0.05)。结论 NMDA受体NR2B亚基在肠管缺血引起的内脏痛形成机制中起重要作用;缺血性内脏痛模型大鼠可用于相关内脏痛发生机制的研究。

Objective To observe the behavioral responses and expression of N-methy-D-aspartate NR2B receptor in dorsal horn of spinal cord in rats＇ visceral pain model induced by ischemic stimulation. Methods Thirty six Sprague-Dawley rats were randomly divided into two groups： shame-operated group （n = 18） and visceral ischemic group （n = 18）. The numerical score for pain behaviors was recorded every 15 minute on the occasion of the minute of 30, 60, 120, 180 and on the 2 nd, 3rd days after operation. Pain score were counted respectively. On the 3rd, 7th and 14th day after operation, 6 rats were collected randomly and all spinal cord of them were divided to collect the L4-5 segments to examine the expression of N methy-D-aspartate NR2B receptor using Immunohistochemistry method. Results As compared with shame-operated group, pain score of visceral ischemia group was increased significantly on the all examine occasion （P 〈0.05） and reached to the maximum on the time of 60 minutes after ligating ratsr colon arter y. The positive nucleus of NR2B expression were located at deep layer of dorsal horn of spinal cord and around central canal. On the 3rd day, there was no significant difference of NR2B expression between visceral ischemic group and shame-operated group （P〉0.05）, while on the 7th and 14th day, the difference became obviously （P 〈0.05）. Compared in same group, the expression of NR2B on 7th day was increased than it on third and fourteenth day （P 〈0.05）. Conclusion N-methy-D-aspartate NR2B receptor play an important role in production mechanism of ratrs visceral pain model induced by ischemia. This kind of model can served for mechanism research of visceral pain.