Co-culture of annulus fibrosus cells and bone marrow mesenchymal stem cells.

To investigate the effect on cell proliferation and extracellular matrix expression of annulus fibrosus (AF) cells when co-cultured with bone marrow mesenchymal stem cells (BMSCs). Primary isolated rabbit BMSCs and AF cells were cultured and harvested cells were placed into a 15-mL centrifugal tube co-culture system in a ratio of 2:1 (A group), 1:1 (B group), and 1:2 (C group). Cell proliferation was evaluated using cell counting kit-8, and mRNA of collagen II and mucopolysaccharide was quantified using real-time polymerase chain reaction (PCR) on Days 7, 14, and 21. The cell count, synthesized collagen II and mucopolysaccharide increased in a time-dependent manner, with a peak at Day 21. Cells in Group B proliferated faster and synthesized more collagen II and mucopolysaccharide than groups A and C, where the difference was significant. AF cells and BMSCs in the ratio of 1:1, cultured using the centrifugal tube three-dimensional co-culture system showed that BMSCs can promote AF cell proliferation and extracellular matrix synthesis.