IMPROVED LONG-TERM BONE-IMPLANT INTEGRATION - EXPERIMENTS IN TRANSGENIC MICE OVEREXPRESSING BOVINE GROWTH-HORMONE

Several recent studies have investigated the effects of growth hormone (GH) on the healing of fractures and bone ingrowth, but with conflict ing results. The negative results may be due to antibody formation aga inst injected GH or because some experimental models are able to prove only positive GH effects. In this study, we wanted to investigate the effect of GH on implant integration in bone. To avoid potential forma tion of antibodies against injected GH, we used a model with transgeni c mice overexpressing bovine GH (bGH). Titanium implants were inserted in the forehead of the mice. 4 months after insertion, the implants w ere cut out en bloc with the surrounding bone. The calcified specimens were cut and ground to a thickness of approximately 10 mu m. Histomor phometry demonstrated significantly more direct bone-to-metal contact in the transgenic mice than in the nontransgenic littermates. Our find ings indicate that systemic administration of GH in humans may improve implant integration in bone.