Department of Spine Surgery, The 1st Affiliated Hospital of Sun Yat-sen University, Guangzhou, Guangdong, China.
Department of Spine Surgery, Shenzhen Second People's Hospital, The 1st Affiliated Hospital of Shenzhen University, Shenzhen, Guangdong, China.
J Orthop Res. 2021 May;39(5):959-970. doi: 10.1002/jor.24793. Epub 2020 Sep 14.
Previous studies have indicated that growth differentiation factor 6 (GDF6) is a potential candidate for intervertebral disc (IVD) degeneration (IDD) treatment. Here, we investigated the effect of GDF6 on IDD by examining changes in disc structure and the expression of inflammatory and pain-related factors. A rat posterior disc puncture model of single segments and three consecutive segments was constructed, and GDF6 or phosphate-buffered solution was administered via intradiscal injection 1 or 2 weeks after surgery. Magnetic resonance imaging showed a clear degeneration signal in the punctured disc, which was inhibited by GDF6. Histological staining revealed that GDF6 did not significantly improve the structure of IVDs in rats 8 weeks after puncture surgery, but it had an inhibitory effect on expression of the tumor necrosis factor-alpha (TNF-α) and interleukin (IL)-1β in the IVD. Furthermore, GDF6 was found to protect the morphology and structure of the IVD 32 weeks after surgery. Mechanical and thermal hyperalgesia tests suggested that GDF6 injection can significantly improve mechanical and thermal-stimulated pain behavior in rats and inhibit the expression of inflammatory factors TNF-α and IL-1β and the pain factor calcitonin gene-related peptide in the dorsal root ganglion. A rat protein array test indicated that GDF6 could reduce the expression of cytokines IL-6, intercellular cell adhesion molecule-1, matrix metalloproteinase-13, IL-1β, and TNF-α and increase the expression of tissue inhibitor of metalloproteinases 1, Transforming growth factor-beta 2, IL-10, and resistin in a TNF-α-induced IDD cell model. Thus, our study demonstrates that GDF6 can improve the structure of the IVD, inhibit the expression of inflammatory and pain-related factors, and improve pain behavior in rats. Clinical Significance: To establish further preclinical research and clinical trials, comprehensive data are needed to validate the regenerative properties of GDF6. Ideally, a regenerative agent should also be able to relieve discogenic pain, achieving the best clinical outcomes.
先前的研究表明，生长分化因子 6（GDF6）是治疗椎间盘退变（IDD）的潜在候选物。在这里，我们通过观察椎间盘结构的变化以及炎症和疼痛相关因子的表达，研究了 GDF6 对 IDD 的影响。构建了大鼠单节段和连续三节段的后椎间盘穿刺模型，并在手术后 1 或 2 周通过椎间盘内注射给予 GDF6 或磷酸盐缓冲液。磁共振成像显示，穿刺后的椎间盘有明显的退变信号，而 GDF6 抑制了这种信号。组织学染色显示，GDF6 并不能显著改善穿刺手术后 8 周大鼠的椎间盘结构，但它对椎间盘内肿瘤坏死因子-α（TNF-α）和白细胞介素（IL）-1β的表达有抑制作用。此外，研究还发现，GDF6 可保护术后 32 周的椎间盘形态和结构。机械和热痛觉过敏试验表明，GDF6 注射可显著改善大鼠的机械和热刺激痛行为，并抑制炎症因子 TNF-α和 IL-1β以及背根神经节中疼痛因子降钙素基因相关肽的表达。大鼠蛋白质芯片试验表明，GDF6 可降低 TNF-α诱导的 IDD 细胞模型中细胞因子 IL-6、细胞间黏附分子-1、基质金属蛋白酶-13、IL-1β和 TNF-α的表达，增加组织抑制剂的表达。金属蛋白酶 1、转化生长因子-β2、IL-10 和抵抗素。因此，我们的研究表明，GDF6 可以改善椎间盘的结构，抑制炎症和疼痛相关因子的表达，并改善大鼠的疼痛行为。临床意义：为了建立进一步的临床前研究和临床试验，需要综合数据来验证 GDF6 的再生特性。理想情况下，再生剂还应该能够缓解椎间盘源性疼痛，实现最佳的临床效果。
