Department of Orthopedics, Qilu Hospital of Shandong University, Jinan, People's Republic of China.
Inflammation. 2017 Apr;40(2):612-622. doi: 10.1007/s10753-017-0508-6.
This study was conducted in order to investigate the function of IL-21 in intervertebral disc degeneration. The serum concentration of IL-21 in patients with lumbar disc herniation (LDH) was examined by ELISA. Immunohistochemistry and western blot analysis were performed to detect the expression of IL-21, a disintegrin and metalloproteinase with thrombospondin motifs (ADAMTS-7), and tumor necrosis factor alpha (TNF-α) in degenerated intervertebral disc (IVD) tissues of human and rat. Moreover, nucleus pulposus (NP) cells were treated with 0, 10, 100, and 1000 ng/mL of IL-21 cytokine with and without AG490. TNF-α, ADAMTS-7, and matrix metalloproteinases-13 (MMP-13) mRNA expression was determined by RT-PCR. The expression of signal transducers and activators of transcription, STAT-1, STAT-3, and STAT-5b, was detected by western blot. IL-21 concentration level is higher in the degenerated group and positively correlates with the visual analog score (VAS). IL-21, ADAMTS-7, and TNF-α can be detected in the degenerative NP tissues in both human and rat degenerated NP tissues. The mRNA expression of ADAMTS-7, TNF-α, and MMP-13 was enhanced after stimulation with IL-21. Compared to control, STAT-1, STAT-3, and STAT-5b expression was also enhanced after IL-21 treatment, with STAT-3 being the most significantly enhanced; furthermore, expression was significantly reduced after treatment with AG490. The mRNA expression of TNF-α was markedly reduced after treatment with AG490 compared to treatment with IL-21 only. IL-21 is involved in the pathological development of IVD degeneration and IL-21 could aggravate IVD degeneration by stimulating TNF-α through the STAT signaling pathway.
本研究旨在探讨白细胞介素 21（IL-21）在椎间盘退变中的作用。通过 ELISA 检测腰椎间盘突出症（LDH）患者的血清 IL-21 浓度。采用免疫组织化学和 Western blot 分析检测人及大鼠退变椎间盘（IVD）组织中 IL-21、解整合素金属蛋白酶与凝血酶 3 型（ADAMTS-7）和肿瘤坏死因子-α（TNF-α）的表达。此外，用 0、10、100 和 1000ng/ml 的 IL-21 细胞因子处理髓核（NP）细胞，并用或不用 AG490 处理。通过 RT-PCR 检测 TNF-α、ADAMTS-7 和基质金属蛋白酶-13（MMP-13）mRNA 的表达。通过 Western blot 检测信号转导和转录激活因子 1（STAT-1）、STAT-3 和 STAT-5b 的表达。退变组的 IL-21 浓度水平较高，且与视觉模拟评分（VAS）呈正相关。在人及大鼠退变 NP 组织中均能检测到退变 NP 组织中的 IL-21、ADAMTS-7 和 TNF-α。IL-21 刺激后 ADAMTS-7、TNF-α 和 MMP-13 的 mRNA 表达增强。与对照组相比，IL-21 处理后 STAT-1、STAT-3 和 STAT-5b 的表达也增强，其中 STAT-3 增强最明显；此外，用 AG490 处理后表达明显降低。与仅用 IL-21 处理相比，用 AG490 处理后 TNF-α 的 mRNA 表达明显降低。IL-21 参与了 IVD 退变的病理发展，通过 STAT 信号通路刺激 TNF-α，IL-21 可能加重 IVD 退变。
