前扣带回TRPC1/4/5通道在小鼠慢性炎性痛所致焦虑样行为中的作用

Role of TRPC1/4/5 channels in the anterior cingulate cortex of mice with anxiety-like behavior induced by chronic inflammatory pain

目的:探讨前扣带回(ACC)中瞬时感受器电位通道1/4/5(TRPC1/4/5)在小鼠慢性炎性痛诱发焦虑样行为过程中的表达变化。方法:将雄性C57/BL6小鼠(n=30)随机分为3组:正常对照组(Control组)、CFA1 d组和CFA 7 d组,小鼠左后肢足底皮下注射完全弗氏佐剂(CFA)建立慢性炎性痛模型。采用小鼠机械痛和热痛敏方法检测痛阈变化,旷场和高架十字迷宫法检测小鼠焦虑样行为,real time RT-PCR和Western Blot方法检测TRPC1/4/5通道表达水平变化。结果:小鼠左后肢足底注射CFA后出现明显的机械性痛敏和热痛敏现象。旷场和高架十字迷宫实验显示CFA诱发炎性痛敏7 d后,小鼠在高架十字迷宫开臂进入次数和时间、旷场中央区活动距离均明显降低,提示慢性炎性痛后小鼠出现显著的焦虑样行为。采用real time RT-PCR和Western Blot实验,观察到炎性痛诱发焦虑样小鼠ACC脑区中TRPC1/4/5通道的mRNA和蛋白表达水平较正常组均出现显著上调。结论:CFA诱发的慢性炎性痛模型中,小鼠出现明显的焦虑样症状,同时ACC脑区的TRPC1/4/5通道表达水平显著升高,提示慢性炎性痛诱发的焦虑样行为可能与痛觉神经通路中ACC脑区的TRPC1/4/5通道蛋白表达有密切关系。

Objective: To investigate the expression changes of transient receptor potential channel 1/4/5(TRPC1/4/5) in the anterior cingulate cortex(ACC) with anxiety-like behavior induced by chronic inflammatory pain in mice.Methods: Male C57/BL6 mice(n = 30) were randomly divided into 3 groups: Control group,CFA 1 d group and CFA7 d group,chronic inflammatory pain model was established by subcutaneously intraplantar injection of CFA in mice left hindpaw. Changes in pain threshold was assessed by mechanical and thermal hypersensitivity. Anxiety-like behaviors were analyzed by open field test and elevated plus maze. Real-time RT-PCR and Western Blot were used to detect the changes of TRPC1/4/5 channels expression levels. Results: Obvious mechanical and thermal pain sensitization were produced after CFA injection in mice left hindpaw. Open field test and elevated plus maze showed that the entries and time in open arm and the distance in central area were both significantly reduced at 7 d after CFA-induced inflammatory pain,suggesting that significant anxiety-like behavior was induced after chronic inflammatory pain in mice. Using real time RT-PCR and Western Blot,the mRNA and protein expression levels of TRPC1/4/5 channel in the ACC of anxietyinduced mice were significantly up-regulated compared with control group. Conclusion: In the CFA-induced chronic inflammatory pain model,mice displayed obvious anxiety-like behaviors and the expression levels of TRPC1/4/5 channel proteins in the ACC were significantly increased,suggesting that the anxiety-like behavior induced by chronic inflammatory pain may be closely related to the expression of TRPC1/4/5 channel proteins in the ACC at the pain neural circuit.