转运蛋白通过激活脊髓背角星胶细胞自噬缓解神经病理性疼痛

TRANSLOCATOR PROTEIN ALLEVIATES NEUROPATHIC PAIN THROUGH ACTIVATING THE SPINAL CORD DORSAL HORN ASTROCYTES AUTOPHAGY

摘要:

摘 要 目的：探讨18kDa转运蛋白(translocator protein, TSPO)通过激活脊髓背角星胶细胞自噬缓解神经病理性疼痛(neuropathic pain, NP)的作用机制。方法：雄性SD大鼠随机分为4组：假手术组（Sham组）、对照组（SNL组）、TSPO受体激动剂Ro5-4864处理组（Ro组）、自噬诱导剂Rapamycin处理组（Rap组）。采用Von Frey hair测量大鼠50%机械缩足阈值 (paw withdrawal threshold, PWT)，在术后第7天(D7)、14天(D14)取损伤侧脊髓样本，采用蛋白印迹技术检测自噬相关蛋白Beclin1、LC3、p62及通路蛋白PGC-1α，采用免疫荧光检测LC3在脊髓背角星胶细胞的表达。结果：1.与Sham相比，SNL组50%PWT从术后第一天开始明显下降，持续到观察结束，脊髓Beclin1、LC3、p62表达明显升高（P<0.01），脊髓PGC-1α表达明显升高，脊髓背角星胶细胞LC3表达信号增强；2.与SNL组相比，Ro组和Rap组50%PWT在D7、D14明显升高，Ro组脊髓Beclin1、LC3表达明显升高（P<0.01），p62蛋白含量先升高后降低，PGC-1α持续升高，D14显著高于同时间SNL组（P<0.01）；3.与Ro组相比，Rap组脊髓D14 Beclin1及D7、D14 LC3差异有统计学意义（P<0.01）。结论：鞘内注射TSPO受体激动剂Ro5-4864能显著缓解神经病理性疼痛，其涉及机制之一可能为通过激活PGC-1α相关途径，而后激活脊髓背角星胶细胞的自噬。

Abstract:

Abstract Objective: Translocator protein(TSPO) can alleviate neuropathic pain.This study was undertaken to explore whether it can activate the astrocytes autophagy in the spinal cord dorsal horn and to explore the possible mechanism .Methods: All male Sprague-Dawley rats were randomly assigned into the following 4 groups: the Sham group,the control group(SNL group),the Ro5-4864 group(Ro group) and the Rapamycin group(Rap group). Von Frey hairs were used to measure the 50% paw withdrawal thresholds (PWT). The protein expressions of Beclin1、LC3、p62 and PGC-1α in the ipslateral spinal cord was detected by western blot and immunofluorescence. Results: 1.Compared with the sham group,the 50%PWT of the SNL group was significantly decreased and the expression of Beclin1、LC3、p62 and PGC-1α were significantly increased(P<0.01). 2. Compared with the SNL group, the 50%PWT of the Ro group and Rap group were significantly increased and the expression of Beclin1, LC3 and PGC-1α in the Ro group were significantly increased(P<0.01). The expression of p62 in the Ro group was decreased compared with SNL group(D14:P<0.01). 3.Compared with the Ro group,the expression of Beclin1 and LC3 were significantly decreased in the Rap group.Conclusion: Intrathecal injection of TSPO agonist Ro5-4864 can alleviate neuropathic pain.One of the possible mechanisms is activating astrocytes autophagy of the spinal cord dorsal horn.This mechanism may be related to PGC-1α relevant pathway.