Preparation of 3D Printing PLGA Scaffold with BMP‐9 and P‐15 Peptide Hydrogel and Its Application in the Treatment of Bone Defects in Rabbits
Xiaomei Wang, Wanjun Chen, Zhe Chen, Yixiu Li, Kai Wu, Yulin Song
Abstract
Objective . To prepare a three‐dimensional (3D) printing polylactic acid glycolic acid (PLGA) scaffold with bone morphogenetic protein‐9 (BMP‐9) and P‐15 peptide hydrogel and evaluate its application in treating bone defects in rabbits. Methods . 3D printing PLGA scaffolds were formed and scanned by electron microscopy. Their X‐ray diffraction (XRD), in vitro degradation, and compressive strength were characterized. BMP‐9 and P‐15 hydrogels were prepared. Flow cytometry was used to detect apoptosis, and an electron microscope was used to evaluate cell adhesion to scaffolds. Alkaline phosphatase (ALP), type 1 collagen (Col‐I), osteocalcin (OCN), runt‐related transcription factor 2 (RUNX2), and osterix (SP7) were detected by western blotting. MicroCT was used to detect new bone formation, and bone tissue‐related protein expressions were determined in the rabbit model with bone defects. Results . The 3D printing scaffolds were cylindrical, and the inner diameter of the scaffolds was about 1 mm. The bread peak with wide distribution showed that the 3D printing only involved a physical change, which did not change the properties of the materials. The degradation rate of scaffolds was 9.38%, which met the requirements of properties of biological scaffolds. The water absorption of the support was about 9.09%, and the compressive strength was 15.83 N/mm 2 . In the coculture of bone marrow mesenchymal stem cells (BMSCs) with scaffolds, the 2% polypeptide hydrogel showed the most obvious activity in promoting the differentiation of BMSCs. Flow cytometry showed that the 0% and 2% groups did not cause obvious apoptosis compared with the control group. Scaffolds with 2% and 4% polypeptide promoted the expression of ALP, COL‐1, OCN, RUNX2, and Sp7 in BMSCs. In vivo experiments showed that the expression of ALP, COL‐1, OCN, RUNX2, and Sp7 protein in the 2% polypeptide scaffold group increased significantly compared with the model group. MicroCT detection demonstrated that the 2% polypeptide scaffold had good bone repair ability. Conclusion . The PLGA scaffolds combined with BMP‐9 and P‐15 peptide hydrogels had good biological and mechanical properties and could repair bone defects in rabbits.