Fig. 4

Pathological morphology of the intervertebral disc and concentration expression of cAMP and PKA. (A) HE staining of nucleus pulposus cells. Scale bar: 20 μm, 40 μm; Toluidine blue staining of cartilage endplate cells. Toluidine blue stain can stain cartilage either purple or light blue. Scale bar: 50 μm. (B) The cAMP level in the intervertebral disc. (C) The level of PKA in the intervertebral disc. Data are expressed as mean ± SD; Asterisks indicate statistical significance (^**P < 0.01 compared to the sham compressed group,^##P < 0.01 compared to the model group)