Fig 1.
(A) schematic drawing representative of functional spine unit and regions of the disc showing the caudal and cranial cartilaginous endplates, the nucleus pulposus and the anterior and posterior annulus fibrosus. The figure also shows the blood supply to the disc (B) Superior view of a spine unit after the removal of the posterior arch. (C) Sagittal view of the mid part of the spine unit, note the nylon stitch in the antero-superior region to maintain the fragment in functional position in all steps of the study. (D) MRI and (E) CT sagittal view with ligaments and paraspinal muscles intact for better contrast.
Table 1.
Details of donor samples in the two groups studied.
Table 2.
Intervertebral disc degenerative status classified by the Pfirrmann scale.
Fig 2.
Endplate openings in the different regions of the disc per group.
In (A) an example of a scanning image from endplate openings and in (B) an example of a binary image of a nucleus pulposus region in the ImageJ software. (C) Middle-aged (younger than 50-years of age) and (D) Old-aged (older than 80-years of age). Observe that in caudal endplates there are more openings in all regions. Endplate openings per 10 mm2 in cranial and caudal endplates above and below the discs of Middle-aged (E) and Old-aged (F). Images acquired from a 10 mm2 area in the Stereo Microscope Discovery V.8. AFa–anterior annulus fibrosus; NP–nucleus pulposus; AFp–posterior annulus fibrosus. (*) p < 0.05; (**) p < 0.01; (***) p < 0.001. ANOVA-test, followed by Bonferroni post-test.
Table 3.
Total number of cells/mm2, % viable cells, and total number of viable cells/mm2 in each region of the disc for Middle- and Old-aged discs.
Fig 3.
(A) Sulphated glycosaminoglycans in different regions of the disc for both groups. Observe the lower contents for old-aged group compared to middle-aged in all regions. In (B) observe the similar distribution of hyaluronic acid. (*) p < 0.05; (**) p < 0.01. ANOVA-test, followed by Bonferroni post-test.
Table 4.
Percentage of disaccharides products formed by the action of chondroitinase AC on glycosaminoglycan of human lumbar intervertebral disc.
Fig 4.
(A) Histological analysis of the human lumbar intervertebral disc stained using picrosirius red and visualized by polarized light microscopy. Observe that in all regions of the disc, in middle-aged, there is a predominance of thick fibres or reddish fibres. In (B), shows the ratio of reddish/greenish collagen fibres identified by split imaging in channels (red-green) and quantified using Image J software. AFa–anterior annulus fibrosus; NP–nucleus pulposus; AFp–posterior annulus fibrosus. (***) p < 0.001. ANOVA-test, followed by Bonferroni post-test.