G/β-TCP composite scaffold facilitates the repairment of cartilage defect in rabbit knee joint

Abstract

Purpose To evaluate the repairment of graphene/β-tricalcium phosphate (G/β-TCP) composite scaffold on cartilage defect in rabbit knee joint. Method The G/β-TCP composite scaffold was prepared and the chemical morphology of G/β-TCP composite was observed by X-ray diffraction (XRD) and scanning electron microscope. The pore size analysis and biomechanical test were performed to test the properties of the material. The composite material containing BMSCs was surgically implanted into the femoral condyle of a full-thickness cartilage defect model in rabbits, and the β-TCP material was used as the control. The visceral tissues of the animals were collected at 2, 4, 8, and 16 weeks, and the pathological changes were observed by HE staining to evaluate the biocompatibility of the material. The G/β-TCP composite material containing BMSCs was implanted into the femoral condyle of rabbit full-thickness cartilage defect model, and β-TCP material was used as control. Creatinine (Cr), alanine aminotransferase (ALT), and C-reactive protein (CRP) were detected by ELISA, and the pathological changes were observed by HE staining. Immunohistochemistry assay was used to detect the expression of type I and II collagen in the transplanted cartilage tissue. Toluidine blue staining was used to observe the growth of cartilage. Results XRD showed that no difference on the X-ray diffraction characteristics was observed between G/β-TCP and β-TCP. The biomechanical test showed that the graphene doped β-TCP material processed higher mechanical strength. Scanning electron microscopy showed that the surface of G/β-TCP material was smoother and the texture was denser. The scaffold combined with BMSCs was transplanted into the full-thickness cartilage defect rabbit model and the results showed that the serum CRP level increased only at 1 month after implantation, and the Cr level increased at 2 months after implantation, while G/β-TCP material showed rare significant pathological changes on the liver, spleen, kidney, brain, and soft tissue around the operation, which indicated a promising biocompatibility. The expression of type I and II collagen in the cartilage tissue of G/β-TCP treated rabbits was dramatically elevated compared to β-TCP at 2 and 3 months after implantation. Conclusion G/β-TCP composite scaffold facilitated the repairment of cartilage defect in rabbit knee joint.