姜黄素下调脊髓Toll样受体4及下游细胞因子减弱大鼠神经病理性痛

Curcumin Alleviates Neuropathic Pain Through Decreasing The Expressions of Proinflammatory Cytokines Produced by TLR4 Pathway in The Spinal Cord of Rats

观察鞘内注射姜黄素对坐骨神经慢性压迫性损伤(CCI)大鼠痛阈和脊髓组织Toll样受体4(TLR4)及TNF-α、IL-1β和IL-10表达的影响.鞘内置管的120只大鼠随机均分为4组:假手术组(Sham),CCI组,溶剂对照组(SC),姜黄素治疗组(Cur,100μg/天),建立CCI大鼠疼痛模型,术后第1、3、7、10和14天鞘内给药并测定痛阈,第3、7天取腰段脊髓第4～6节段(L4～L6)以Real-time PCR与Western blotting方法检测TLR4、HMGB1 mRNA和蛋白质的表达,ELISA法观察脊髓组织中TNF-α、IL-1β及IL-10表达变化.与Sham组相比,CCI组大鼠机械性痛阈与热痛阈显著降低(均P<0.05),同时脊髓组织TLR4、HMGB1 mRNA和蛋白质的表达明显增加(均P<0.05),TNF-α、IL-1β与IL-10的含量也明显升高(均P<0.05);鞘内注射姜黄素明显降低脊髓TLR4、高迁移率族蛋白1(HMGB1),TNF-α和IL-1β的表达,显著升高脊髓IL-10的表达,同时明显改善CCI大鼠疼痛行为(P<0.05).姜黄素减轻神经病理性疼痛可能与下调TLR4途径促炎症因子表达有关,抑制TLR4途径有望成为治疗神经病理性疼痛的新策略.

In this study, we investigate the efffects of curcumin trathecal injection on pain threshold and the expressions ofTLR4, TNF-α, IL-1β and IL-10 in the spinal cord of rats with chronic constrictive injury （CCI）. 120 males Sprague-Dawley （SD） rats fitted with intrathecal catheters were randomly divided into four groups： sham group （Sham）, CCI group （CCI）, solvent control group （SC）, and curcumin treated group （Cur, 100 μg/d）. Neuropathic pain was produced by CCI of right sciatic nerve as described previously. On the 1st, 3rd, 7th, 10th, and 14th day after surgery, 100μg curcumin dissolved in DMSO 10 μl was administered intrathecally once daily, and then pain threshold was measured. The expressions of TLR4, HMGB 1 mRNA, and protein in lumbar spinal cord 4-6（L4-L6） were assessed by RT-PCR and Western blotting, respectively. The levels of TNF-α, IL-1β and IL-10 in the spinal cord were detected by ELISA. We found that the paw withdrawl threshold （PWT） and paw withdrawl latency （PWL） were significantly decreased after CCI （P 〈 0.05）, and the expressions of TLR4, HMGB 1 mRNA and protein were significantly increased （P 〈 0.05）; the levels of TNF-α and IL-1β in the spinal cord were also significantly increased after CCI compared with those in the sham goup （P 〈 0.05）. Curcumin markedly attenuated CCI- induced mechanical allodynia and thermal hyperalgesia through inhibiting the activation of TLR4 pathway and production of inflammatory cytokines. These results demonstrated that curcumin alleviated neuropathic pain may be by decreasing the expression inflammatory cytokines produced by TLR4 pathway.