Background   Tissue engineering, as a new technique, has attracted more and more attention from spinal medicine researchers. However, there is still no clear standard in the selection of seed cells in tissue engineering.

  Objective   To obtain and identify cartilage end plate stem cells (CESC) and bone marrow mesenchymal stem cells (BMSC), and find out whether CESC has the potential as seed cells for tissue engineering by comparing with BMSC.

  Methods   The phenotype of chondrocytes in primary cultured SD rats was identified by toluidine blue staining, and the characteristics of CESC and BMSC stem cells were identified by single clone screening. Then, the three lines cells were induced to verify the characteristics of CESC and BMSC stem cells; and the P3 generation of CEP, CESC and BMSC were taken for non-contact co-cultivation. At 1 d, 3 d, 5 d, and 7 d, CCK-8 was used to detect the proliferation of CEP in the lower layer of Transwell chamber in the three groups and the proliferation curve was drawn. Flow cytometry was used to detect the changes of CEP apoptosis in the middle and lower compartments of the three groups after 7 days of co-cultivation. Finally, RT-qPCR was used to detect the changes in the expression of CEP phenotype gene proteoglycan (ACAN), type Ⅱ collagen (COLⅡ), and sex determining region Y box protein 9 (Sox9).

  Results   Toluidine blue staining showed that the primary cultured CEP secreted cartilage-related polysaccharides such as glycosaminoglycan (GAG), and had characteristics of polygonal shape and paving stone-like distribution. After the three-line induced differentiation of CESC and BMSC isolated by monoclonal method, red calcium nodules were observed by alizarin red staining, a large number of round red lipid droplets around the cells were observed by oil red O staining, and aggregate proteoglycans secreted specifically by chondrocytes were observed by fuchsin staining. CCK-8 assay showed that the proliferation ability of CESC group and BMSC group was stronger than that of CEP group, and the proliferation ability of CESC group was stronger than that of BMSC group, and there was no difference in the level of CEP apoptosis among the three groups. RT-qPCR results showed that the expression of ACAN, COL2A1 and Sox9 in the three groups of CEP co-culture increased from the 1st day to the 7th day, and the expression level peaked on the 3rd day. There was no significant difference in the expression of phenotypic genes ACAN, COL2A1 and Sox9 among the three groups on the 1st and 7th day. On the 3rd and 5th day, the expression of phenotypic genes in CESC group was significantly higher than that in BMSC group and CEP group (P＜0.05).

  Conclusion   Both CESC and BMSC can enhance the proliferation of CEP and the expression of cartilage phenotype by non-contact co-culture, and the effect of CESC is better.