Constant compression decreases vascular bud and VEGFA expression in a rabbit vertebral endplate ex vivo culture model

PLoS One. 2020 Jun 25;15(6):e0234747. doi: 10.1371/journal.pone.0234747. eCollection 2020.

Abstract

Summary of background data: 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).

Objective: 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.

Methods: 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.

Results: 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.

Conclusions: 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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Blood Vessels / physiology*
  • Culture Techniques
  • Gene Expression Regulation*
  • Intervertebral Disc / blood supply*
  • Intervertebral Disc / metabolism*
  • Male
  • Rabbits
  • Stress, Mechanical*
  • Vascular Endothelial Growth Factor A / metabolism*

Substances

  • Vascular Endothelial Growth Factor A

Grants and funding

JWZ received support from the National Natural Fund Project of China (No.81804120); LGZ received support from the National Natural Fund Project of China (No.81930118), Standardized construction project of rehabilitation service ability and technical platform of TCM Department of orthopedics in Beijing(No.110019), Scientific Research Project of Chinese Academy of Traditional Chinese Medicine?Research on Rehabilitation-related Diagnosis and Treatment Technology of Characteristic Traditional Chinese Medicine ZZ13-YQ-038; SQW received support from the State General Administration of Physical Education (No: HXKT2017001).