神经病理痛模型大鼠前扣带皮层不同水平磷酸化细胞外信号调节激酶表达差异比较

目的探讨痛相关情绪模型大鼠前扣带皮层(ACC)磷酸化细胞外信号调节激酶(p-ERK)的分布特点。方法将12只雄性SD大鼠随机分为对照组和模型组。模型组大鼠进行右侧腰5脊神经结扎制做模型。采用右后足跖机械痛阈检测观察行为变化,旷场实验和高架O迷宫实验检测痛相关情绪变化,免疫荧光技术检测同侧前扣带皮层前囟前3.2、2.7及2.2mm 3个水平p-ERK表达。结果大鼠经神经病理痛模型制做成功后机械痛阈显著下降,焦虑样行为产生。前扣带皮层前囟前3.2、2.7及2.2mm水平p-ERK阳性细胞表达量分别为11.89±2.57、32±4.67和17.56±2.04。对照组相应的p-ERK阳性细胞表达量分别为12.44±2.16、10±0.87和10.11±1.36。除前囟前3.2mm水平对照组与模型组相比没有显著性差异(P0.05)之外,其他两个水平p-ERK阳性细胞表达量模型组显著高于对照组(P0.01)。结论神经病理性疼痛能诱发大鼠焦虑情绪的产生及ACC脑区pERK的表达增高,这种变化可能主要与ACC脑区前囟前2.7及2.2mm水平p-ERK的变化相关,而与前囟前3.2mm水平无关。

Comparisons of expression of phosphorylated extracellular signal-regulated kinase in different levels of anterior cingulate cortex in the rat with neuropathic pain

Objective To observe the distribution features of phosphorylated p44/42 extracellular signal-regulated kinase(p-ERK) induced by affective pain in the anterior cingulate cortex (ACC) of the rat. Methods Twelve male SD rats were randomly divided into the control group (n=6) and spinal nerve ligation (SNL) group (n=6). The rats of the SNL group were exposed to unilateral L5 spinal nerve ligation (SNL) surgery. The behavior was examined by mechanical pain thresholds (MPTs) and the pain affect was measured using open-field test, elevated zero maze. The expressions of p-ERK in ACC (AP 3.2,2.7,2.2mm from Bregma) were detected with immunofluorescence test. Results In comparison with the control group, the unilateral mechanical pain threshold in the SNL group decreased significantly after operation. The operation also resulted in pronounced anxiety-like behavior. The p-ERK labelled cells in different levels of ACC(AP 3.2,2.7,2.2mm from Bregma) of SNL rats were (11.89±2.57),(32±4.67 ) and (17.56±2.04 ), respectively, while the control group rats were (12.44±2.16),(10±0.87 ) and (10.11±1.36). These data indicated that compared with the control group, the expressions of p-ERK in ACC(AP 2.7,2.2mm from Bregma) increased significantly in the SNL group after operation(P<0.01), besides for the level of ACC(AP 3.2mm from Bregma) (P>0.05). Conclusion The results suggest that the neuropathic pain can result in anxiety-like behavior and increased expressions of p-ERK in ACC of the rat. This change may be closely related to the expressions of p-ERK in ACC(AP 2.7，2.2mm from Bregma), but not to the level of ACC(AP 3.2mm from Bregma).