International Journal of Nanomedicine (Oct 2017)
Evaluation of synergistic osteogenesis between icariin and BMP2 through a micro/meso hierarchical porous delivery system
Abstract
Qian Wang,1–4 Lingyan Cao,4,5 Yang Liu,6 Ao Zheng,4,5 Jiannan Wu,4,5 Xinquan Jiang,4,5 Ping Ji1–3 1Department of Oral and Maxillofacial Surgery, Stomatological Hospital of Chongqing Medical University, 2Chongqing Key Laboratory of Oral Diseases and Biomedical Sciences, 3Chongqing Municipal Key Laboratory of Oral Biomedical Engineering of Higher Education, Chongqing, 4Oral Bioengineering and Regenerative Medicine Lab, Shanghai Key Laboratory of Stomatology & Shanghai Research Institute of Stomatology, National Clinical Research Center of Stomatology, 5Department of Prosthodontics, Ninth People’s Hospital, Shanghai Jiao Tong University School of Medicine, 6The State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, People’s Republic of China Abstract: BMP2 is well known as an outstanding growth factor for inducing new bone formation. However, improvements are still required to use BMP2 effectively and expand its clinical application due to the potential side effects at high doses. In this study, icariin (IC), a type of traditional Chinese medicine, was originally proposed to be a cooperative factor for BMP2. An alkaline phosphatase (ALP) activity assay showed that IC promoted BMP2 osteogenesis in a concentration-dependent manner with significant enhancement at 38.4 µM versus that for BMP2 at 0.8 µg/mL. Furthermore, we developed a composite hierarchical porous scaffold (SF/SBA15; composed of micropores of silk fibroin [SF] scaffold and mesopores of SBA15) for the controlled delivery of BMP2 and IC. This composite scaffold was investigated by a series of physical characterizations and displayed good in vitro cell biocompatibility. In addition, the composite scaffold also showed the degradation rate of 12% dry weight loss and a slight change in the microstructures within 10 days. Moreover, BMP2 and IC were loaded into the SF and SBA15 structures, respectively, of the SF/SBA15 scaffold. This protein/drug loading system (SFBMP2/SBA15IC) provided delivery of BMP2 with an initial burst release of 60.9%±0.9% in the first 24 hours and a gradual release over the subsequent 6 days to 97.9%±0.8%, whereas IC exhibited a burst release of 64.2%±0.7% in the first 24 hours, followed by a sustained release to 92.4%±0.8% over 10 days. With the prolonged local retention and interaction duration of BMP2 and IC, the SFBMP2/SBA15IC scaffold provided better osteogenic differentiation than other groups with different loading modes of BMP2 or IC, as determined by ALP staining and quantitation and Alizarin red staining. Finally, the results of quantitative real-time polymerase chain reaction analysis indicated that the SFBMP2/SBA15IC scaffold induced a significantly higher increase in the RUNX2, ALP, COL I, and OCN expression levels of cocultured bone marrow mesenchymal stem cells than other payload composite scaffolds. This study suggests that a micro/meso hierarchical porous delivery system of BMP2 and IC ensures osteogenic synergy and demonstrates promise for bone tissue engineering. Keywords: synergistic delivery, hierarchical structure, controlled release, porous scaffold, mesopore, growth factor
