LOCAL APPLICATION OF GROWTH HORMONE INDUCES INCREASED IMMUNOEXPRESSION OF IGF-I ON CRANIOFACIAL BONE DEFECTS REPAIR – A PILOT STUDY

Abstract

The aim is to evaluate the local effect of different concentrations of growth hormone (GH) on the repair of craniofacial bone defects, through histological, histomorfometric, and insulin-like growth factor I (IGF-I) immunoexpression assessments. Critical defects (5 mm) were performed in 32 Wistar rats. The animals were divided into four groups: Group C (Control); Group S (Sponge-collagen); Group GH 0.08 mL; GH 0.104 mg; Group GH 0.1mL. Local applications were performed 3 times a week until the rats were euthanized at 60 days. The data were submitted to ANOVA and Tukey's test (P < 0.05). A healing process with predominance of collagen bers and bone neoformation near the edges of the defect was observed in groups C and S. Islands of bone neoformation were observed at the center and edges of the defect in groups GH 0.08 and GH 0.1. In GH 0.1, the bone was more compact, and the defect was completely closed in some specimens. Bone neoformation was signicantly higher in the GH-treated groups. All the specimens stained positive for IGF-I, and this immunoexpression was signicantly higher in Group GH 0.1. In conclusion, locally applied GH signicantly favored bone repair in rat calvaria, and a higher dose of GH increased the immunoexpression of IGF-I.