[Promotion effect of notochordal cells conditioned medium on proliferation and differentiation of bone marrow mesenchymal stem cells].

OBJECTIVE: To investigate the effect of notochordal cells (NCs) conditioned medium (NCCM) on the proliferation and differentiation of bone marrow mesenchymal stem cells (BMSCs).

METHODS: NCs and BMSCs were isolated from the thoracolumbar intervertebral disc and the femurs of 4-week-old Japanese white rabbits, respectively. NCs were cultured with DMEM/F12 medium containing 15% FBS for 5 days to prepare NCCM. The experiment consisted of 2 groups: BMSCs were cultured with NCCM in experimental group and with DMEM/F12 medium containing 15% FBS in control group. The proliferation of BMSCs was assessed by cell counting kit-8 at 1, 3, 5, 7, 9, and 14 days after culture; the expression of proteoglycan and collagen type II were determined by immunofluorescence and real-time fluorescent quantitative PCR at 7 and 14 days after culture.

RESULTS: NCs and BMSCs were successfully isloated. At 5, 7, 9, and 14 days, the number of BMSCs in the experimental group was significantly more than those in the control group (P < 0.05). At 7 and 14 days, there was no expression or less expression of proteoglycan and collagen type II in the control group; however, there was a lot of expression of proteoglycan and collagen type II in the experimental group, and the expressions were higher at 14 days than at 7 days. At 7 and 14 days after culture, the mRNA expressions of proteoglycan and collagen type II were significantly higher in the experimental group than in the control group (P < 0.05), and at 14 days than at 7 days in the experimental group (P < 0.05).

CONCLUSION: NCCM can promote the proliferation and the differentiation of BMSCs into chondroyte-like cells, which provides the basis for NCs and BMSCs as seed cells in the treatment of degenerative disc disease.