Fig. 2

Histological findings in rats’ IVDs L2–L3. Control group, regular structure: a, d Hematoxylin and Eosin stain (H&E), g, j Picrosirius Red/Alcian Blue stain (P&A). High-fat diet: b fissures and separation in the lamella of the annulus fibrosus, the nucleus pulposus bulging towards the vertebra, structural changes of the subchondral bone; e fragment of 2b: the nucleus pulposus bulging towards the vertebra, H&E; h decrease in the intensity of the staining of matrices in the inner annulus fibrosus; k fragment of 2 h: destructive changes in nucleus pulposus, P&A. Compression: c fissures and separation in the lamella of the annulus fibrosus, decrease in the number of cells, and changes in the matrix structure observed in the nucleus pulposus, degenerative changes in the subchondral bone; f fragment of 2c: gaps developing in the border between the annulus fibrosus and the nucleus pulposus, H&E; i the intensity of the Alcian blue matrix staining (cyan colour) in the inner annulus fibrosus greater than the control; l fragment of 2i: the formation of clusters of cells, P&A