Sustained Release of Demineralized Bone Matrix Protein in Osteoporotic Rats.

Demineralized bone matrix protein (DBM) was considered highly effective in stimulating bone healing. The objective of the study was to explore the use of tricalcium phosphate (TCP) delivery system to continuously deliver DBM in an osteoporotic condition and to evaluate changes in bone density and preservation of the spine. Ovariectomized Sprague Dawley rats were divided into three equal groups (n=16 per group). Animals in group I served as control, animals in groups II and III were surgically implanted with either empty (SHAM) or DBM filled TCP implants adjacent to L4/L5. Eight animals from each group were euthanized at 2 and 8 weeks post implantation. Femurs were evaluated for changes in density, and the lumbar spine was evaluated for changes in the endplate. Results of this study revealed (1) TCP implants were capable of delivering DBM for long duration, (2) use of sustained delivery of DBM did not induce untoward effects in the vital organs or in the uterus, fallopian tubes, or vaginal tissues, (3) DBM had no effect on chondrocyte differentiation in the spine, and (4) DBM did not increase bone density in osteoporotic female rats.