General Orthopedics Department, Wangjing Hospital, China Academy of Chinese Medical Sciences, Beijing, China.
Key Laboratory of Beijing of Palasy Technology, Wangjing Hospital, China Academy of Chinese Medical Sciences, Beijing, China.
PLoS One. 2020 Jun 25;15(6):e0234747. doi: 10.1371/journal.pone.0234747. eCollection 2020.
The vascular buds in the vertebral endplate (VEP) are the structural foundation of nutrient exchange in the intervertebral disc (IVD). VEGF is closely related to angiogenesis in the endplate and intervertebral disc degeneration (IDD).
To investigate the effects of static load on vascular buds and VEGF expression in the VEP and to further clarify the relation between IDD and VEGF.
IVD motion segments were harvested from rabbit lumbar spines and cultured under no-loading conditions (controls) or in custom-made apparatuses under a constant compressive load (0.5 MPa) for up to 14 days. Tissue integrity and the number of vascular buds were determined, and the concentrations and expression of Aggrecan, COL2a1, and VEGFA in the VEPs were assessed after 3, 7, and 14 days of culturing and then compared with those of fresh tissues.
Under the constant compression, the morphological integrity of the VEPs was gradually disrupted, and immunohistochemistry results showed a significant decrease in the levels of Agg and COL2a1. During the static load, the number of vascular buds in the VEPs was gradually reduced from the early stage of culture, and ELISA showed that the constant compressive load caused a significant decrease in the VEGFA and VEGFR2 protein concentrations, which were consistent with the immunohistochemistry results. Western blot and RT-PCR results also showed that the loading state caused a significant decrease in VEGFA expression compared with that of fresh and control samples.
Constant compression caused degeneration of the VEP as well as a decreased number of vascular buds, thereby accelerating disc degeneration. VEGFA is involved in this process. We anticipate that regulating the expression of VEGFA may improve the condition of the lesions to the vascular buds in the endplates, thus enhancing the nutritional supply function in IVD and providing new therapeutic targets and strategies for the effective prevention and treatment of IDD.
椎体终板（VEP）中的血管芽是椎间盘（IVD）营养交换的结构基础。VEGF 与终板和椎间盘退变（IDD）中的血管生成密切相关。
研究静态负荷对 VEP 中血管芽和 VEGF 表达的影响，进一步阐明 IDD 与 VEGF 的关系。
从兔腰椎中采集 IVD 运动节段，在无负荷条件下（对照）或在定制装置下在恒定压缩负荷（0.5 MPa）下培养，最长可达 14 天。培养 3、7 和 14 天后，确定血管芽的数量和完整性，并评估 VEP 中 Aggrecan、COL2a1 和 VEGFA 的浓度和表达，然后与新鲜组织进行比较。
在持续压缩下，VEP 的形态完整性逐渐被破坏，免疫组织化学结果显示 Agg 和 COL2a1 的水平显著降低。在静态负荷下，VEP 中的血管芽数量从培养早期逐渐减少，ELISA 显示恒定压缩负荷导致 VEGFA 和 VEGFR2 蛋白浓度显著降低，与免疫组织化学结果一致。Western blot 和 RT-PCR 结果也表明，与新鲜和对照样本相比，加载状态导致 VEGFA 表达显著降低。
持续压缩导致 VEP 退化和血管芽数量减少，从而加速椎间盘退变。VEGFA 参与了这一过程。我们预计调节 VEGFA 的表达可能会改善血管芽在终板上的病变状况，从而增强 IVD 的营养供应功能，并为有效预防和治疗 IDD 提供新的治疗靶点和策略。
