Abstract
Introduction
The intervertebral disc is avascular and remains unknown if it has the capacity to maintain viable cells inside over the years. The vascularization of the endplate has a direct influence on the nutrition to the disc cells. This study aimed to analyze the vascularization of the endplate and its relation to the density of viable cells in lumbar intervertebral discs of young and old adult humans.
Materials and Methods
A total of 28 lumbar intervertebral discs were used and separated into two groups: Group 1 (n = 15; younger than 50 years; Pfirrmann ≤ 3) and Group 2 (n = 13; elder or equal to 80 years, Pfirrmann ≥ 4). Vascularization of the endplates was analyzed using Stereo Microscope Discovery V.8. Cell viability was assessed by MTT method. The cell density was measured by PicoGreen technique using amount of DNA as an estimate of total cell number.
Results
The viable cells remained steady in relation to the total cell density. The inferior endplate presented the highest number of holes (p < 0.05). The greater number of cells was found in the annulus fibrosus (p < 0.05). There was a positive correlation (p < 0.05) between the density of viable cells and vascular openings in the inferior endplate.
Conclusion
The inferior endplate has the main supply of blood vessels to nourish the intervertebral disc and has direct bearing on the number of viable cells.
Acknowledgments
This work was supported by INFAR/UNIFESP Confocal and Flow Cytometry Facility and by grants from the “Fundacao de Amparo à Pesquisa do Estado de São Paulo” (FAPESP: Grant number: 2009/54793–6). D.E.M. was supported by a PhD's fellowship grant from CAPES (Coordenacao de Aperfeicoamento de Pessoal de Nível Superior).