Fine structure of cartilage canal and vascular buds in the rabbit vertebral endplate

Abstract

<jats:sec> <jats:title>Object</jats:title> <jats:p>The vascular terminations (vascular buds) in the bone–disc junction area are structurally very similar to cartilage. In all previous studies to date, however, the roles of cartilage canals and vascular buds were mainly discussed using histological and transparent sections but not electron microscopic sections. The purpose of this study was to clarify the ultrastructure of the vascular bud seen in the bone–disc junction in comparison to the cartilage canal.</jats:p></jats:sec> <jats:sec> <jats:title>Methods</jats:title> <jats:p>Japanese white rabbits from 2 days to 6 months of age were used in this study. The bone–disc junctions were examined by microangiogram and light and electron microscopy, and morphological changes and their association with the age of the animals were noted.</jats:p></jats:sec> <jats:sec> <jats:title>Results</jats:title> <jats:p>The fine structure of the vascular bud was similar to that of the cartilage canal that nourished the growing cartilage. They were composed of arteries, veins, capillaries, cells resembling fibroblasts, and macrophages. The capillaries in the cartilage canal were all the fenestrated type. Vascular buds were seen over the entire bone–cartilage interface, with maximum density in the area related to the nucleus pulposus. They projected into the bone–disc junction area from the vertebral body contacting the cartilaginous endplate directly.</jats:p></jats:sec> <jats:sec> <jats:title>Conclusions</jats:title> <jats:p>The results of this study clarify the formation process and ultrastructure of the vascular bud seen in the bone–disc junction. The authors found a strong structural resemblance between the vascular bud and the cartilage canal and hypothesize that the immature cells seen surrounding the cartilage canal and vascular bud represent a common precursor for the 3 main types of connective tissue cells seen during early vertebral development.</jats:p></jats:sec>

Lycorine Suppresses Endplate-Chondrocyte Degeneration and Prevents Intervertebral Disc Degeneration by Inhibiting NF-κB Signalling Pathway

“…Vascular channels [41-43] that bring nutrients to both the avascular IVD [36, 65] and the CEP itself have been identified in the vertebral endplate. The size of the vascular channels might be implicated in IVD degeneration [66].…”

“…Among these cytokines, MIF [5, 37] not only plays a role in CEP degeneration [37-40] but also functions as a positive regulator of proinflammatory cytokines (e.g., TNF-α, IL-1β, and IL-6) and thus stimulates adjacent disc tissue degeneration. More importantly, the cartilage canal and vascular buds in the vertebral endplate are specific fine structures [41-43] that can transport drugs to vertebral endplate by systemic administration [44-48], rendering the CEP as an ideal drug target for reducing IVD degeneration. Together, the aforementioned findings collectively suggest that the CEP represents a potential therapeutic target for the treatment of IVD diseases [49, 50].…”

Predictors of conservative treatment for pyogenic spondylitis

“…Nevertheless, the disease remains a neurological and life threating condition 8,9) . Pyogenic spondylitis arises from haematogenous spread of bacteria at the endplate and subchondral bone of the vertebrae 10) . The abscess invades directly from the subchondral lesion to the intervertebral disk (avascular in adult) and the infection extends into the epidural and paravertebral spaces.…”

Endplate calcification and cervical intervertebral disc degeneration: the role of endplate marrow contact channel occlusion

“…Similarly to previous studies on lumbar IVD samples [1,23], we have observed that the correlation between endplate degeneration and the number of endplate openings is the strongest for those MCCs that hold capillary buds [3]. However, in contrast to other studies, we have chosen to investigate openings 10-50 μm in diameter, as animal studies report that capillary buds, within the endplate's cartilage can be between 5-50 μm in size [15]. However, as mentioned earlier, we did not include into our analysis openings smaller than 10 µm, as they have been found to be mostly artefacts [1].…”

“…Capillary permeability increases in this order, and the morphological features of the endothelium indicate organ specificity [2]. The vascular buds were found to be fenestrated capillaries, which are usually observed in metabolically very active tissues such as endocrine glands, kidneys, intestinal mucosa and dorsal root ganglion [15,16]. This would mean that there is enhanced permeability and metabolism in both the cartilaginous endplate and the IVD.…”