INSULIN ENHANCEMENT OF IN-VITRO WOUND-HEALING IN FETAL-RAT PARIETAL BONES

Purpose: This study evaluated the effect of insulin on fracture in fet al rat intramembranous bone using an organ culture system in which bon e mineralizes in vitro. Materials and Methods: Twenty-day-old fetal ra t parietal bones were fractured parallel to the frontal plane and cult ured in a serum-free medium with or without insulin for 4 to 12 days. They were then processed for light microscopy. Results: In the specime ns not treated with insulin, bony bridges were observed in less than 1 0% on day 4 and 8, and only 45% on day 12, In bones treated with insul in at 10(-6) mol/L, bony bridges were observed in 73% on day 4 and 100 % on day 8 and 12. No callus or cartilage formation was observed durin g the wound repair process, indicating that intramembranous ossificati on occurred. Conclusion: These findings suggest that insulin has a dir ect effect on bone cells, which enhances the healing of fractures in i ntramembranous bone.