Fig. 3From: Vitamin D inhibits TNF-α induced apoptosis of human nucleus pulposus cells through regulation of NF-kB signaling pathwayIdentification of nucleus pulposus cells. A The gross morphology of the nucleus pulposus cells was observed. B Safranin O staining of nucleus pulposus cells. C Toluidine blue staining of nucleus pulposus cells. D Immunohistochemically for collagen II of nucleus pulposus cellsBack to article page