活性氧激活的脊髓星形胶质细胞参与瑞芬太尼诱发的痛觉过敏

Activation of Spinal Astrocyte via Reactive Oxygen Species Contributes to Remifentanilinduced Hyperalgesia

【目的】观察活性氧能否通过激活脊髓星形胶质细胞从而介导瑞芬太尼诱发的痛觉过敏。【方法】72只SD大鼠随机分成6组,每组12只:对照组(C)、瑞芬太尼组(R)、瑞芬太尼+腹腔注射生理盐水组(R+Si.p)、瑞芬太尼+腹腔注射活性氧清除剂N-叔丁基-α-苯基硝酮(PBN)组(R+PBN)、瑞芬太尼+鞘内注射生理盐水组(R+Si.t)、瑞芬太尼+鞘内注射星形胶质细胞抑制剂L-α-氨基己二酸(L-α-AA)组(R+L-α-AA)。成年雄性SD大鼠静脉输注瑞芬太尼4μg/(kg·min)2 h建立痛敏模型,采用von Frey及Hargreaves法观察抑制活性氧生成或星形胶质细胞激活对瑞芬太尼诱发痛觉过敏的影响。鞘内注射线粒体荧光探针Mito SOX Red探测脊髓线粒体中活性氧产生水平及分布,免疫荧光以及免疫印迹方法观察脊髓背角星形胶质细胞的激活。【结果】静脉输注瑞芬太尼后24 h后引起大鼠机械阈值(R组:30±2.58;C组:50±1.80;P<0.05)和热痛阈值(R组:5.5±1.70;C组:10.0±1.21;P<0.05)显著下降。与对照组相比,瑞芬痛敏组大鼠脊髓GFAP于输注瑞芬后2h表达显著上调(R组:0.16±0.009;C组:0.10±0.008;P<0.01),且脊髓神经元活性氧水平显著增加(R组:0.14±0.008;C组:0.04±0.005;P<0.01)。预先腹腔内注射PBN后第1天不仅显著抑制大鼠脊髓星形胶质细胞激活(R组:0.16±0.009;R+PBN组:0.10±0.007;P<0.01),且减轻瑞芬太尼诱导的机械痛敏(R组:30.0±2.58;R+PBN组:45.0±2.81;P<0.05)和热痛敏(R组:5.5±1.70;R+PBN组:9.4±1.00;P<0.05)。【结论】活性氧激活的星形胶质细胞介导了瑞芬太尼诱发的痛觉过敏,抑制活性氧介导的星形胶质细胞激活可能是减轻瑞芬太尼诱发痛觉过敏的潜在靶点。

[Objective] To investigate the role spinal astrocyte activated by reactive oxygen species （ROS） in a rat model of remifentanil-induced hyperalgesia. [Methods] Seventy-two rats were randomly separated into 6 groups, 12 per group：group control （C）, group remifentanil （R）, group of remifentanil＋ intraperitoneal injection of saline （R＋Si.p）, group of remifentanil＋intraperitoneal injection of ROS scavenger phenyl-N-tert-butylnitrone （PBN）（ R＋PBN）, group of remifentanil＋intratheeal injection of saline （R＋Si.t）, group of remifentanil＋intratheeal injection of astroeyte inhibitor L-α-aminoadipate （L-α-AA）. Mechanical and thermal hyperalgesia was induced by continuous infusion of remifentanil 4 μg/（kg ·min）for 2 h. Von Frey test and Hargreaves method were selected toassess the effect of astrocyte inhibitor or ROS scavenger on remifentanil-induced mechanical and thermal hyperalgesia. To detect the expression level of ROS in the spinal cord, mitochondrial superoxide indicator MitoSox Red was intrathecally injected 24 h before remifentanil infusion. Activation of spinal astrocyte was evaluated by immunofluorescence and Western blot analysis. [Results] Intravenous infusion of remifentanil induced mechanical （R：30.0 ± 2.58; C：50.0 ± 1.80; P 〈 0.05） and thermal hyperalgesia （R： 5.5 ± 1.70; C ： 10.0 ± 1.21 ; P 〈 0.05）. Compared with control group, activation of astrocyte （R： 0.16 ± 0.009 ; C ： 0.10 ± 0.008 ; P 〈 0.01） and increased ROS level （R：0.14 ± 0.008; C：0.04 ± 0.005 ;P 〈 0.01） in the spinal cord were detected in 2 h following remifentanil infusion. Furthermore, pretreatment with ROS scavenger PBN inhibited activation of spinal astrocyte （R：0.16 ± 0.009; R＋PBN：0.10 ＋ 0.007; P 〈 0.01） as well as mechanical （R：30.0 ± 2.58; R＋PBN：45.0 ± 2.81 ;P 〈 0.05） and thermal hyperalgesia （R：5.5±1.70; R＋PBN：9.4 ± 1.00; P 〈 0.05） induced by remifentanil. [Conclusion] ROS-mediated activation of spinal astrocyte might contribute to remifentanil-induced hyperalgesia. Inhibition of astrocyte activation induced by ROS in the spinal cordmight be a therapeutic strategy to prevent remifentanil-induced hyperalgesia.