Ursolic acid loaded-mesoporous hydroxylapatite/ chitosan therapeutic scaffolds promote the bone regeneration

Abstract

Background: Mesoporous hydroxylapatite (MHAP) could play an important role in bone regeneration, and UA (Ursolic acid) also promote the osteogenic differentiation. Accordingly, we developed the UA loaded MHAP scaffolds to cure bone defects. In vitro, we synthesize biomaterial scaffolds. By SEM, XRD, EDS and FTIR, we test the performance of the hybrid scaffolds. By drug release, ALP staining, Alizarin red staining, and Western blotting, we test the osteo-inductive properties of scaffold materials. In vivo, We verify bone regeneration through a rat skull defect model.Results: The MHAP is a rod-shaped structure with a length of 100~300nm and a diameter of 40~60nm. The critical structure gives the micro scaffold a property of control release due to the pore sizes of 1.6~4.3 nm in hydroxyapatite and the hydrogen bonding between the scaffolds and UA drugs. The released UA drugs could notably promote the expression of osteogenic-related genes (COL1, ALP, OPG) and osteogenic-related proteins (BMP-2, RUNX2 and COL1). Both the images of μCT and the results of double fluorochrome labelling demonstrated that therapeutic scaffolds promoted the bone regeneration. We obtained the similar results through immunohistochemistry. Conclusions: The MHAP-CS-UA scaffolds have good osteo-inductivity and bone regeneration. And they will be the novel and promising candidates to cure the bone disease.