The mechanism of cartilage regeneration by buffy coat and the pre-clinical study

Abstract Background Autologous bone marrow buffy coat transplantation possesses obvious advantages in the therapy of cartilage defects. However, there is no definite research on the specific effective components of bone marrow buffy coat and its mechanism of cartilage regeneration. Moreover, bone marrow buffy coat is difficult to fix onto the damaged cartilage area. We assessed the effect of using hyaluronic acid(HA) as a gel scaffold mixed with autologous bone marrow buffy coat to fix cartilage defect. Methods and Materials We extracted the bone marrow from the anterior superior iliac crest of rabbit, centrifuged to obtain buffy coat, and analyzed the components of buffy coat by ELISA. Buffy coat+fibrin/HA group, MSC+fibrin/HA group, MSC+TGF-β+fibrin/HA group were cultured in vitro and observed by staining. In addition, we made damage to the femoral condyle of rabbits, and divided them into groups: HA group, buffy coat group, buffy coat with HA group. Each group was assessed for cartilage regeneration by visual observation, histological at 4 weeks and 8 weeks, and biochemical analysis at 8 weeks postoperatively. One-way ANOVA and LSD were used for statistic analysis. Results Buffy coat have a variety of growth factors, inflammatory factors and anti-inflammatory factors that stimulate the MSCs’ regeneration. Buffy coat can differentiate into cartilage without TGF-β stimulation in vitro. The cartilage regeneration ability of buffy coat and buffy coat+HA is strong, and the combination of buffy coat and gel scaffold HA can make cartilage formation ability more stable in vivo. Conclusion MSC and cytokines in buffy coat synergistically promote cartilage regeneration. Gel scaffold HA enhances the effect of buffy coat on cartilage attachment and regeneration of cartilage defects.