Kinetics of bone growth factors gene expression during heterotopic bone formation. Bone trabeculae (OST), inflammatory tissue (INF) and adipose tissue (ADP) were isolated from the implants using laser microdisection and used to isolate total RNA to determine by RT-PCR the indicated bone growth factor during the heterotopic bone formation. Numbers indicate the day when the implant was obtained after the implantation. Results are present as mean and standard deviation from three dogs in the indicated time points. Two independent experiments were run with similar results. Asterisks represent statistical significance comparing the groups in each time point (p < 0.05).