The bone inductive capacity of decalcified bone matrix modified by diphenylhydantoin

Induction of endochondral bone by demineralized bone matrix from diabetic rats

In this investigation we examined the osteoinductive potential of demineralized bone matrix derived from chronically diabetic (streptozotocin-induced) rats. Long-Evans rats (28-31 days) were made diabetic with a single injection of streptozotocin (65 mg/kg) and provided food and water ad lib for 2 months. Diaphyseal shafts of femurs and tibias removed from the diabetic rats and their sibling controls were dehydrated, pulverized, sieved to 74-420 micron particles, and demineralized. Matrix was then bioassayed for its ability to induce endochondral bone on day 11 following subcutaneous implantation over the thorax of Long-Evans rats. The resulting plaques of tissue were subjected to histological analysis, determination of alkaline phosphatase activity, and calcium content. Bone matrix derived from diabetic animals proved to be a significantly better inducer of endochondral bone than did control matrix.

The osteo-inductive properties of bone matrix from rats pretreated with indomethacin

Decalcified bone matrix pieces were prepared from growing rats treated for 3 weeks with subcutaneous injections of indomethacin 2 mg/kg/day or saline, and implanted into growing rats. Of the 16 recipients with 'saline implants', 8 received saline and another 8 indomethacin 2 mg/kg/day in subcutaneous injections. In another 16 recipients with 'indomethacin implants', 8 received saline and 8 indomethacin. As in previous studies, it was found that indomethacin exerted a mild inhibition of new bone formation expressed as decreased amount of ash weight in implants. The amount of ash weight and 45Ca specific activity of implants in recipients with implants from indomethacin-treated donor animals was not altered. These findings indicate that indomethacin is unable to modify the osteo-inductive properties of bone matrix.