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Caption : positioning of a white label as a guide for along which raman measurements were acquired (with a direction from the trabecular bone of the vertebral body to the intervertebral disc).

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Caption : raman image (1000 × 1693 um) generated from raman mapping of the endplate transition zone at the nucleus (white light image of the sample shown in panel (a)), depicting the intensity of amide iii ratio (1245 cm-1/ 1265 cm-1). the yellow subregion marked in panel (a) corresponds to the mapped area with the exact size of the reconstructed image in panel (b). the red dotted line indicates the spectroscopic ‘’tidemark’’ between bone and cartilage.