慢性痛大鼠模型前扣带皮层内小胶质细胞活化与细胞因子表达

目的:观察慢性炎症性疼痛大鼠前扣带皮层(ACC)中小胶质细胞标记物(CD14,IBA1)及促炎症细胞因子(IL-1β,TNF-α)的表达变化。方法:单侧足底注射完全弗氏佐剂(CFA)诱导大鼠慢性炎症性疼痛,用RT-PCR检测ACC中CD14、IL-1β、TNF-αmRNA的表达,用免疫组织化学染色观察ACC中IBA1免疫阳性小胶质细胞的变化。结果:足底注射CFA后4 h、3 d双侧ACC中CD14 mRNA表达较生理盐水(NS)组有显著增加(P<0.001);CFA后4 h、3 d、14 d双侧ACC中IL-1βmRNA表达较NS组有显著增加(P<0.001);CFA后3 d、14 d双侧ACC中TNF-αmRNA表达较NS组有显著增加(P<0.001)。CFA 3 d组双侧ACC中IBA1免疫阳性小胶质细胞胞体变大、突起变粗。结论:ACC中小胶质细胞的活化以及IL-1β和TNF-α的表达增加可能在慢性炎症性疼痛的产生和维持中发挥作用。

The microglia activation and cytokine expression in the anterior cingulate cortex of rat with chronic pain

Objective: To investigate the expression of microglia marker(CD14,IBA1) and proinflammatory cytokine(IL-1β,TNF-α) in the anterior cingulate cortex(ACC) of rat with chronic inflammatory pain.Methods: The chronic inflammatory pain was induced by unilateral intraplantar injection of Complete Freund’s Adjuvant(CFA) in rat.The expression of CD14,TNF-α and IL-1β mRNA in ACC was detected by RT-PCR.The IBA1-immunoreactive(IBA1-IR) microglia was detected by immunohistochemistry.Results: The expression of CD14 mRNA in bilateral ACC was increased at 4 h and 3 d after CFA injection(P<0.001,compared with the normal saline(NS) group).CFA injection induced marked increases of IL-1β mRNA expression in bilateral ACC at 4 h,3 d and 14 d(P<0.001,compared with the NS group) and TNF-α mRNA expression in bilateral ACC at 3 d and 14 d(P<0.001,compared with the NS group).The cell bodies of IBA1-IR microglia became bigger and the processes became thicker and shorter in animals at 3 days after CFA injection than that in control animals.Conclusion: These results suggest that the activation of microglia and the increased expression of IL-1β,TNF-α in the ACC may play a role in the development and maintenance of chronic inflammatory pain.