外周炎性痛刺激诱导杏仁核内星形胶质细胞激活及细胞因子的表达

Astroglial activation and cytokine expression in the amygdala induced by peripheral inflammation pain

为了观察完全弗氏佐剂(CFA)外周刺激对杏仁核内星形胶质细胞标记物(GFAP)以及细胞因子(IL-β,TNF-α)表达的影响,本研究结合行为学检测、RT-PCR和Westernblot方法,观察了大鼠后爪注射CFA后的痛行为变化,并检测了在不同时间点杏仁核内GFAP、IL-β和TNF-α在基因水平和蛋白水平的表达变化。结果显示:注射CFA后,注射侧后爪出现热痛敏和机械性触诱发痛;大鼠的热痛敏在14d时基本恢复正常,但机械性痛敏持续至21d时仍未恢复正常;GFAP在亚急性期和慢性期有显著增加;而IL-β和TNF-α在急性期、亚急性期及慢性期均有增加。上述结果表明:星形胶质细胞可能与疼痛的维持相关,而细胞因子表达的增加可能在痛觉过敏的产生和维持中均起重要作用。

To explore the effects of complete Freunds adjuvant （CFA） administrated into peripheral region on the expressional changes of astrogllal marker （ glial fibrillary acidic protein, GFAP） and cytokines （ IL-β, TNF-α） in the amygdala, the behavior observation and RT- PCR and Western blot techniques were used to examine the changes of heat hyperalgesia and mechanical allodynia following intraplantar administration of CFA in hindpaw of the rat and the expressional changes of mRNA and protein of GFAP, IL-β and TNF-α in the amygdala at different time points. The results showed that the hindpaw of the rat in the injection side exhibited chronic thermal hyperalgesia and mechanical allodynia after injection CFA. The thermal hyperalgesia was recovered on day 14, but the mechanical allodynia lasted more than 21 days. The increase of GFAP in amygdala was observed only at subacute and chronic phases of inflammation, whereas the expression of IL-β and TNF-α in amygdala showed a significant increase during all phases （acute, subacute and chronic） of inflammation. The present results indicate that the activation of astrecytes may be involved in the maintenance of inflammatory pain and enhanced cytokines expression might have roles in both development and maintenance of behavioral hypersensitivity.