Abstract：
Autophagy is a critical player in lumbar intervertebral disk degeneration (IDD), and autophagy activation has been suggested to prevent the apoptosis of nucleus pulposus cells (NPCs). Myricetin has anti-cancer, anti-inflammatory, and antioxidant potentials and can activate autophagy. Thus, this study focused on the roles and mechanisms of myricetin in IDD. A puncture-induced rat IDD model was established and intraperitoneally injected with 20-mg/kg/day myricetin. Histopathological changes of intervertebral disks (IVDs) were assessed by hematoxylin and eosin staining and Safranin O/Fast Green staining. The isolated NPCs from IVDs of healthy rats were stimulated with IL-1β to mimic IDD-like conditions. The roles of myricetin in cell apoptosis, extracellular matrix (ECM) degradation, autophagy repression, and the JAK2/STAT3 pathway activation were examined by cell counting kit-8, flow cytometry, western blotting, real-time quantitative polymerase chain reaction, and immunofluorescence staining. Myricetin treatment attenuated the apoptosis and ECM degradation, and enhanced autophagy in the IL-1β-treated NPCs, whereas the myricetin-mediated protection was limited by autophagy inhibition. Mechanistically, myricetin activated autophagy through blocking the JAK2/STAT3 signaling. In vivo experiments revealed that intraperitoneal injection of myricetin activated NPC autophagy to relieve puncture injury in rats. Myricetin prevents IDD by attenuating NPC apoptosis and ECM degradation through blocking the JAK2/STAT3 pathway to enhance autophagy.
摘要：
自噬是腰椎间盘退变(IDD)的关键因子,自噬激活已被认为可以防止髓核细胞（NPCs）的凋亡。杨梅素有抗癌作用,抗炎,和抗氧化潜能，并能激活自噬。因此，本研究主要探讨杨梅素在碘缺乏病中的作用及机制。建立穿刺诱导的大鼠IDD模型，并腹腔注射20-mg/kg/天的杨梅素。通过苏木精和伊红染色以及SafraninO/FastGreen染色评估椎间盘（IVD）的组织病理学变化。用IL-1β刺激来自健康大鼠的IVD的分离的NPC以模拟IDD样条件。杨梅素在细胞凋亡中的作用,细胞外基质（ECM）降解，自噬抑制，和JAK2/STAT3通路的激活通过细胞计数试剂盒-8，流式细胞术，西方印迹,实时定量聚合酶链反应，和免疫荧光染色。杨梅素处理减轻细胞凋亡和ECM降解，并在IL-1β处理的NPCs中增强自噬，而杨梅素介导的保护受到自噬抑制的限制。机械上,杨梅素通过阻断JAK2/STAT3信号通路激活自噬。体内实验表明，腹膜内注射杨梅素可以激活NPC自噬，从而减轻大鼠的穿刺损伤。杨梅素通过阻断JAK2/STAT3途径增强自噬，减弱NPC凋亡和ECM降解，从而预防IDD。
