Fig. 1

Design of coculture experiments with human bone marrow-derived mesenchymal stem cells (MSCs) and intervertebral disc cells without cell contact. Four experimental groups were cultured for 21 days. Controls were MSCs cultured in osteogenic medium (positive control) and MSCs cultured in growth medium (negative control). The experimental groups were cocultures of MSCs with either nucleus pulposus cells (NPCs) or annulus fibrosus cells (AFCs)