Use of demineralized bone matrix protein in osteoporotic rats: a histological evaluation - biomed 2009

Osteoporosis is a disease characterized by structural deterioration of bone tissue, leading to fragile bone with an increased risk for fractures. Bone morphogenetic proteins (BMPs) are supplemental bone graft materials that have osteoconductive properties of serving as a scaffold for bone to grow on and osteoinductive capability of stimulating the patient's own stem cells and growth factors to grow new bone. Osteoblast cells in osteoporotic bone have the ability to produce BMPs and other factors needed for adequate bone formation when activated, demonstrating that there are factors that can serve as stimulus for fracture repair in osteoporosis. The objective of this study was to deliver a cascade of growth factors from demineralized bone (DBM), a rich composite of BMP-2, BMP-4, and BMP-7, to the fracture defect site in an effort to enhance osteoporotic fracture healing. 72 female ovariectomized (OVX) rats were divided into six treatment groups: intact control, OVX control, intact + drill defect (sham), OVX + drill defect (sham), intact + drill defect + DBM, and OVX + drill defect + DBM. Ovariectomy induced osteoporosis. DBM was delivered in a sustained manner via a novel local drug delivery device, tricalcium phosphate combined with lysine (TCPL). At 2 and 4 weeks post implantation, animals in each group were sacrificed, the femurs were retrieved and underwent histological analysis. Other surrounding and vital organs were also harvested and analyzed to study the systemic effects of DBM. The results suggest that DBM was effective in increasing osteocyte number en route to restoring periosteal and endosteal area in both intact and OVX animal populations.