Fig.1.

Block diagram of calculation of afferent vascular bud relative area and cartilage endplate (H&E staining)

(a) Vascular area was analyzed by square method and the percentage of vascular area to the whole was calculated; (b) Tidemark was used as separatrix, the thicknesses of calcified layer and non-calcified layer in front 1/3, middle point, and post 1/3 of median sagittal plane in nucleus pulposus were measured, and average values were calculated