乙酸致内脏痛大鼠孤束核及胸髓中P2X4受体表达的变化

THE CHANGES OF P2X_4 RECEPTOR EXPRESSION IN NUCLEUS OF TRACTUS SOLITARIUS AND THE DORSAL HORN OF THORACIC CORD AFTER VISCERAL PAIN INDUCED BY ACETIC ACID

本文探讨了乙酸致内脏痛模型大鼠孤束核及胸髓背角内P2X4受体表达的时程变化。将SD大鼠随机分为6组:空白对照组、内脏痛10、30、60、90和180min组,分别检测各组大鼠行为学以及孤束核、胸髓背角浅层内P2X4受体的表达变化。结果表明,乙酸致内脏痛后各组大鼠均出现典型的扭体行为,内脏痛指数在60、90和180min组最高,30min组其次,10min组最低,各组之间的差别有统计学意义(P<0.01);各内脏痛组P2X4阳性产物在孤束核及胸髓背角浅层表达明显增高,产物呈绿色点状,见于细胞胞膜、突起、胞浆,其时程变化是10min出现表达,30min进一步增高,60min达到顶峰,90min开始下降,至180min进一步降低。此结果表明延髓孤束核及胸髓背角浅层内的P2X4受体在内脏伤害性刺激后表达增加,60min达到高峰。

We studied the time course of changes of P2X4 receptors expression in the nucleus of tractus solitarius （NTS） and dotal horn of the thoracic cord in rat with the visceral pain （VP） induced by i.p. injection of acetic acid. Thirty-six male SD rats were randomized into 6 groups： Control group, VP for 10, 30, 60, 90 and 180 min groups （n =6 for each group）. The degree of VP was evaluated by visceral pain index, according to the Schmauss exponential method. The expression of P2X4 receptors was implemented by using immunofluorescent method. We found that the writhing hehavior of rats with VP for 60 min, 90 min and 180 rain groups were more serious than that of rats with VP for 10 rain and 30 min groups, respectively. The expression of P2X4 receptors were significantly increased in NTS and the superficial layers of thoracic dorsal horn, appearing as green dot in cytoplasm, cell membrane and processes in all test groups. Image-analysis demonstrated that the expression of P2X4 receptors presented at 10 min, increased at 30 min, peaked at 60 min and declined after 90 min survival time. These results indicate that acetic acid induced visceral pain can increase the expression of P2X4 receptors in NTS and the dorsal horn of the thoracic cord, which peaked at 60 min.