EFFECT OF INSULIN-LIKE GROWTH FACTOR-I ON ZYGOMATIC ARCH BONE REGENERATION - A PRELIMINARY HISTOLOGICAL AND HISTOMETRIC STUDY

A number of physicians have attempted to pharmacologically manipulate the healing of bony fractures with a variety of agents such as growth hormone, thyroxine, chondroitin sulfate, and parathyroid hormone. Thus far, results from these experiments have been inconclusive. Previous research dealing with insulinlike growth factors has centered on cultu res of osteoblast-like cells and has demonstrated a stimulatory effect on hone collagen synthesis, which may in fact play a critical role in the process of bone formation itself. The purpose of this investigati on was to examine the effects of a genetically engineered growth facto r, insulin growth factor type I, on midfacial fracture healing. In 24 adult male Sprague-Dawley rats, a standardized defect was created with in the midportion of each zygomatic arch. One-half were treated with i nsulin growth factor type I administered with an osmotic infusion pump and the other half served as control subjects. At 2, 4, 8, and 12 wee ks, animals from each group were killed and specimens of the defect ob tained. Data were collected from radiographs and histological studies to compare the extent of bony repair. From this study, it appears that insulin growth factor type I could exert a potentiating effect on the repair of midfacial bone defects.