Subcutaeneous and Intramuscular Implantations of Porcine Bone Morphogenetic Proteins

Bone Morphogenetic Proteins (BMPs) are polypeptides isolated from mammals including humans. BMPs have the ability to induce healing of osteoperiosteal defects. However, benefits from the osteogenic potential of auto graft bone are restricted due to limited donor source. Therefore, readily available osteogenic inducing material such as Porcine Bone Morphogenetic Proteins is essential. Objectives: To determine the biocompatibility of Porcine Bone Morphogenetic Proteins and to compare it to spongostan, a clinically accepted absorbable gelatin sponge. Methods: Thirty nine Wistar rats, 50 days old were used for subcutaneous and intramuscular implantation of test (Porcine BMPs) and control (Spongostan) samples. The duration of the study was 7 days, 28 days and 90 days. The rats were acclimatized for a period of 10 days prior to commencement of the study. Twelve hours light / night cycle was implemented. Each animal received two test and two control implants. The subcutaneous implants were placed in the dorsal area while the intramuscular implants were placed in the gluteal muscles. Each animal was observed 2 hours after implantation and twice a day thereafter. Any local, systemic and behavioral abnormalities were recorded. The animals were weighed every seven days. Thirteen animals were sacrificed at the end of each observation period. The subcutaneous and intramuscular test and control implant sites were subjected to histopathological examination. The analyses were done using Fisher's Exact Test (p< 0.005). Results: Histopathology showed difference in granulation tissue, encapsulation and vascularization of the subcutaneous and intramuscular test and control implants. Conclusion: Porcine BMPs induce moderate to severe regenerative tissue at implant sites.