Can rhBMP-2 Containing Collagen Sponges Enhance Bone Repair in Ovariectomized Rats?: A Preliminary Study

Abstract

With an aging population the frequency of postmenopausal fractures is increasing. Methods to enhance the repair of osteoporotic bone repair therefore become more important to reduce the society burden of care. We asked if absorbable collagen sponges containing recombinant human bone morphogenetic protein-2 (rhBMP-2) have the potential to enhance bone repair. We randomly assigned 40 rats into the ovariectomy and sham operation groups. A segmental defect was created in the right tibia 12 weeks after ovariectomy. rhBMP-2-containing absorbable collagen sponges were implanted into the defect in half of the animals in each group. We analyzed radiographs and histological sections and performed three-point bending tests to assess repair. Radiological scores in the rhBMP-2 applied rats were higher than those in controls at the end of 8 weeks after tibial osteotomy. The specimens failed under higher loads in the rhBMP-2-applied groups and histology revealed a higher fracture healing score, including callus formation, bone union, marrow changes, and cortex remodeling. We observed no adverse tissue responses such as fibrous connective tissue formation and inflammatory cellular infiltration. rhBMP-2 in absorbable collagen sponges enhanced bone repair in segmental tibial defects of ovariectomized rats. The sponges with rhBMP-2 appeared to enhance bone repair.

Effects of local delivery of BMP2, zoledronate and their combination on bone microarchitecture, biomechanics and bone turnover in osteoporotic rabbits

“…It has been shown that local application of BMP2 significantly promotes spinal fusion, accelerates facture healing and enhances the repair of bone defects192021. Studies have also demonstrated that local BMP2 delivery induced prominent increases of bone formation rate in osteoporotic animals2223.…”

Combined Use of Low-Intensity Pulsed Ultrasound and rhBMP-2 to Enhance Bone Formation in a Rat Model of Critical Size Defect

“…In addition, orthogonal radiographs of harvested femora were obtained at sacrifice. Radiographs were scored for callus formation, quality of union, and bone remodeling by 2 independent blinded observers according to a published scoring system 28 .…”

Effects of Ovariectomy and Corticosteroid-Induced Osteoporosis on the Osteoinductivity of rhBMP-2 in a Segmental Long-Bone Defect Model

“…20 In comparison, a hyaluronic acid (HA)-based carrier is injectable 21 Some studies have shown that rhBMP-2 increases the fusion rate or bone healing in osteoporosis animal models. [22][23][24] In addition, in ovariectomy sheep models, rhBMP-7 was delivered by inserting a poly-lactic glycolic acid microsphere to improve the vertebral body strength. 25 However, such studies showed only that rhBMP-2 and rhBMP-7 triggered new bone formations in osteoporosis models.…”