Effect of ErhBMP-2-loaded β-tricalcium phosphate on ulna defects in the osteoporosis rabbit model

Tse-Yin Huang; Chang-Chin Wu; Pei-Wei Weng; Jian-Ming Chen; Weng-Ling Yeh

doi:10.1016/j.bonr.2020.100739

Effect of ErhBMP-2-loaded β-tricalcium phosphate on ulna defects in the osteoporosis rabbit model

Bone Rep. 2020 Dec 10:14:100739. doi: 10.1016/j.bonr.2020.100739. eCollection 2021 Jun.

Authors

Tse-Yin Huang¹, Chang-Chin Wu^{2

3

4}, Pei-Wei Weng^{5

6}, Jian-Ming Chen⁷, Weng-Ling Yeh^{7

8}

Affiliations

¹ Ph.D. Program for Biotech Pharmaceutical Industry, School of Pharmacy, China Medical University, Taichung 40402, Taiwan.
² Department of Orthopedics, National Taiwan University Hospital, College of Medicine, National Taiwan University, Taipei 10002, Taiwan.
³ Department of Biomedical Engineering, Yuanpei University of Medical Technology, Hsinchu 30015, Taiwan.
⁴ Department of Orthopedics, En Chu Kong Hospital, New Taipei City 23702, Taiwan.
⁵ Department of Orthopaedics, School of Medicine, College of Medicine, Taipei Medical University, Taiwan.
⁶ Department of Orthopaedics, Shuang Ho Hospital, Taipei Medical University, Taiwan.
⁷ Department of Orthopedic Surgery, Chang Gung Memorial Hospital-Linkou, Tao-Yuan 33305, Taiwan.
⁸ Bone and Joint Research Center, Chang Gung Memorial Hospital, Taoyuan, Taiwan.

Abstract

Purpose: Autografts, the gold standard treatment for large bone defects, present complications, especially in conditions with reduced bone-repair capacity, such as osteoporosis. Escherichia coli-derived recombinant human bone morphogenesis protein-2 (ErhBMP-2), was used in this study to improve the osteoinductivity of β-tricalcium phosphate (β-TCP). This study evaluated the bone-repair capacity of ErhBMP-2-loaded β-TCP on osteoporosis rabbit model, relative to the sole use of autograft and β-TCP treatments.

Methods: The osteoporosis rabbit model was induced through ovariectomy and glucocorticoid dosing; 2-cm segmental ulnar defects were created, which were treated with either autograft, β-TCP alone, or ErhBMP-2-loaded β-TCP or left untreated. The quality of newly formed ulnae was evaluated 8 weeks after ulnar surgery through micro-CT, biomechanical, histological, and histomorphometric assessments.

Results: The osteoporosis rabbit model was developed and maintained till the end of the study. The maximal load and stiffness in the ErhBMP-2-loaded TCP group were significantly higher than those in the autograft group, whereas the TCP-alone group performed similarly as did the untreated group in the force loading and stiffness tests. According to the micro-CT evaluation, the ErhBMP-2-loaded TCP group had significantly higher bone volume relative to the autograft and TCP-alone groups. Histological assessments revealed better defect bridging and marrow formation in the ErhBMP-2-loaded TCP group relative to the TCP-alone group. Mineral apposition rates were significantly higher in the ErhBMP-2-loaded TCP and autograft groups than in the TCP-alone and untreated groups.

Conclusion: Relative to autografts, ErhBMP-2-loaded TCP, as an alternative grafting material, provides better or comparable healing on critical-sized long bone defects in the osteoporosis rabbit model.

Keywords: BMC, bone mineral content; BMD, bone mineral density; BV, bone volume; ErhBMP-2; ErhBMP-2, Escherichia coli-derived recombinant human bone morphogenesis protein-2; Osteoporosis rabbit model; ROI, region of interest; Tricalcium phosphate; Ulna defect; β-TCP, β-tricalcium phosphate.