摘要目的：采用慢性坐骨神经结扎（ CCI）模型，观察大鼠痛行为及前扣带皮层（ ACC）、中脑导水管周围灰质（ PAG）、延髓头端腹内侧核（ RVM）和脊髓腰膨大Fos蛋白表达的变化，探讨ACC对脊髓伤害性信息的调节。方法成年雄性SD大鼠48只，随机分6组为：Naive组、Sham组（假手术组，仅分离出大鼠左侧坐骨神经）、CCI组（大鼠左侧坐骨神经结扎）、CCI＋P组（左侧坐骨神经结扎术后14 d，行为学测试前45 min帕罗西丁10 mg／kg i．p．）、ACC?Sham组（正常大鼠，双侧ACC定点注射0．9％ NaCl，1μl／侧）、ACC?AP5组（ CCI术后13 d，双侧 ACC定点注射 NMDA受体拮抗剂 AP?525 mM，1μl／侧）。相应于CCI术后第14天的时间点，明暗箱实验、强迫游泳实验、机械痛阈、热痛阈测定各组大鼠行为学，用免疫组化方法检测ACC、PAG、RVM和脊髓腰膨大Fos蛋白表达的变化。结果（1）各组术前行为学差异无统计学意义。与Naive组相比，CCI组大鼠术后2周术侧出现机械性痛阈下降（P＜0．01）；明暗箱测试中，大鼠在明箱内时间缩短（P＜0．01）、穿梭次数减少（P＜0．01）；强迫游泳潜伏期延长（P＜0．01）。 CCI＋P组、ACC?AP5组术后与Naive组相应时间点相比差异无统计学意义。各组术后热痛阈值的差异无统计学意义（P＞0．05）。（2） CCI组术后手术侧（左侧）ACC内Fos蛋白表达（4920．6±1053．7）、非手术侧（右侧）ACC内Fos蛋白表达（2059．3±409．1），PAG腹外侧区（VlPAG）内Fos蛋白表达（9074．8±2320．3），RVM内Fos蛋白表达（6195．4±895．0），手术侧（左侧）脊髓背角内Fos蛋白表达（15148．8±3080．2）、非手术侧（右侧）脊髓背角内Fos蛋白表达（6400．2±1558．4）明显高于Naive组[ACC左侧（716．5±202．5）、ACC右侧（828．5±200．0），VlPAG（3255．1±458．9），RVM（2299．8±517．0），脊髓背角左侧（3850．0±684．5）、脊髓背角右侧（3441．4±570．2）]，均差异有统计学意义（均P＜0．01）。 CCI＋P 组手术侧 ACC 内 Fos 蛋白表达（2776．4±820．1）、非手术侧 ACC 内 Fos 蛋白表达（1120．5±141．4），VlPAG内Fos蛋白表达（4002．2±1171．8），RVM内Fos蛋白表达（2938．9±910．3），手术侧脊髓背角内Fos蛋白表达（8742．0±1131．0）、非手术侧脊髓背角内Fos蛋白表达（3933．1±858．9）低于CCI组，差异有统计学意义（P＜0．01）。 ACC?AP5组手术侧ACC内Fos蛋白表达（3623．1±667．4）、非手术侧ACC内Fos蛋白表达（696．5±164．8），VlPAG内Fos蛋白表达（5668．8±1403．3），RVM内Fos蛋白表达（3972．3±851．7），手术侧脊髓背角内Fos蛋白表达（10675．4±1725．3）、非手术侧脊髓背角内Fos蛋白表达（3818．3±1085．1）均低于CCI组，差异有统计学意义（均P＜0．01）。结论 CCI大鼠ACC通过下行易化系统参与脊髓伤害性信息传递的调节。

abstractsObjective To observe pain behavior and the expression of Fos in the related brain re? gions,including Anterior Cingulate Cortex ( ACC) ,Periaqueductal Gray ( PAG) ,Rostral ventromedial nucle?us ( RVM) in chronic constrictive injury ( CCI) rats and to explore whether ACC modulate spinal nociceptive transmission through endogenous descending facilitatory system. Methods A total of 48 male SD rats were randomly divided into six groups:Naive group,Sham group ( just separated the left sciatic nerves without liga?tion) ,CCI group ( the left sciatic nerve was ligated) ,CCI+P group ( on the 14 th day after surgery,intraper?itoneal injection of 10 mg/kg paroxetine 45 min before behavior test) ,ACC?Sham group ( bilateral microin?jection of 0.9% NaCl in ACC,1μl/each side) and ACC?AP5 group ( bilateral microinjection of AP5 25 mM in ACC,1μl/each side on the 13th day after surgery) . On the 14th day after light?dark transition test,forced swimming test,paw?withdrawal mechanical threshold( PWMT) and paw?withdrawal thermal patency( PWTL) were performed,the rats were terminally anesthetized and ACC,PAG,RVM and the spinal cord was rapidly removed,and then the expression of c?fos was measured by immunohistochemistry. Results ( 1) Rats in CCI group demonstrated nociceptive hypersensitivity and depressive?like behaviors compared with Naive rats, while rats in CCI+P group and in ACC?AP5 group showed less nociceptive hypersensitivity and less depres?sive?like behaviors compared with CCI group. (2)Compared with Naive group,the number of c?fos positive neurons in the bilateral ACC (left,surgery side,4920.6±1053.7;right,2059.3±409.1),VIPAG (9074.8± 2320.3),RVM (6195.4±895.0) and bilateral spinal cord (left,15148.8±3080.2;right,6400.2±1558.4) was significantly enhanced in CCI group, especially in the left side. In contrast, the amount of fos labeled neurons declined in the bilateral ACC (left,2776.4±820.1;right,1120.5±141.4),VIPAG (4002.2± 1171.8),RVM (2938.9±910.3) and bilateral spinal cord (left,8742.0±1131.0;right,3933.1±858.9) in CCI+P group and also declined in the bilateral ACC (left,3623.1±667.4;right,696.5±164.8),VIPAG (5668.8±1403.3),RVM (3972.3±851.7) and bilateral spinal cord (left,10675.4±1725.3;right,3818.3± 1085.1) in ACC?AP5 group. Conclusion Endogenous descending facilitatory system may contribute to ACC modulating spinal nociceptive transmission.