THE EFFECTS OF SUSTAINED DELIVERY OF ESTROGEN AND DEMINERALIZED BONE MATRIX PROTEINS ON BONE IN OVARIECTOMIZED FEMALE RATS

摘要

Osteoporosis affects over ten million persons within the United States and is estimated to cost the healthcare system $18 billion dollars a year. Approximately 1.5 million persons will be diagnosed with an osteoporotic fracture and the epidemiological data reflects that prevalence of the osteoporotic fractures is four times more common than having a stroke. The current treatments strategies for osteoporosis are geared toward inhibiting the osteoclast cell resorption of bone, and not on the osteoblast bone formation. The use of demineralized bone matrix proteins (DBM) has been shown to be effective in healing osteoporotic bone fractures within a four week time period. Our goal was to deliver in a sustained manner DBM over an eight week period and compare bone strength and bone histology to osteoporotic untreated animals, osteoporotic animals given sustained delivery of physiological estrogen, as well as naive control (animals with ovary intact). Our results showed estrogen administered in a sustained fashion was able to reverse the decline in bone strength and re-establish the bone quality similar to ovary intact controls. DBM administered in a sustained manner showed similar bone quality and strength to osteoporotic control animals. Administration of DBM to mature bone in a sustained fashion may be ineffective in inducing osteoblast function or reversing osteoclast activity. It is possible that DBM may be more effective on immature bone cells.