A Preclinical Study of Bone Marrow Buffy Coat Components and Cartilage Regeneration

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 their mechanism of cartilage regeneration. Moreover, bone marrow buffy coat is difficult to fix onto the damaged cartilage area. We evaluated the composition of Buffy coat and the combined use of hyaluronic acid (HA) as a scaffold material for repairing cartilage defects. Methods and Materials: We extracted the bone marrow from the anterior superior iliac crest of the rabbit, centrifuged it to obtain buffy coat, and analyzed the components of buffy coat by enzyme-linked immunosorbent assay (ELISA). Buffy coat+fibrinogen/HA group, mesenchymal stem cell (MSC)+fibrinogen/HA group, MSC+ Transforming Growth Factor β(TGF-β)+ fibrinogen/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 statistical 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.