A metaphyseal fracture rat model for mechanistic studies of osteoporotic bone healing.

A metaphyseal fracture rat model for mechanistic studies of osteoporotic bone healing. Eur Cell Mater. 2019 May 22;37:420-430 Authors: Wong RM, Thormann U, Choy MH, Chim YN, Li MC, Wang JY, Leung KS, Cheng JC, Alt V, Chow SK, Cheung WH Abstract Most osteoporotic fractures occur at metaphyseal regions of long bones. The present study proposed a clinically relevant animal model that satisfied: i) induction of osteoporosis, ii) unilateral complete osteotomy at metaphysis, iii) internal fixation. 6 months old female Sprague-Dawley rats (n = 64) were randomly divided into the ovariectomised-metaphyseal osteotomy (OVX, n = 32) and metaphyseal osteotomy (SHAM, n = 32) groups. The metaphyseal-osteotomy model was created with a plate-fixation of the osteotomy and assessed by X-ray, micro-computed tomography, histomorphometry and mechanical testing at weeks 1, 3 and 6. X-ray results showed complete healing of metaphyseal osteotomy at week 6. Histology showed 3 stages of metaphyseal healing. Stage 1 was characterised by fibrous tissue, consisting of disorganised orientation of collagen fibres, and infiltration of immune cells. At stage 2, a transitional zone consisting of maturing fibrous tissue and differentiating mesenchymal cells with early trabecular bone formation and disorganised woven bone were observed. During stage 3, cortical bone ends unified and woven bone underwent transformation to lamellar bone. OVX group healing was significantl...
Source: European Cells and Materials - Category: Cytology Tags: Eur Cell Mater Source Type: research