Hydroxyapatite/polyamide 12 composite membrane as implant in intracorporeal sites

Abstract

To evaluate the angiogenic and osteoinductive ability of implant consisting of hydroxyapatite powder incorporated into polyamide 12 membrane, thirty rats had this implant concomitantly placed at three intracorporeal sites (subcutaneous, omentum, and femur periosteum). Dosages of liver enzymes, urea, and creatinine serics demonstrated absence of hepatotoxicity and nephrotoxicity. Bone marrow samples, analyzed by the micronucleus test, demonstrated absence of toxicogenetic potential. The intracorporeal sites were assessed by light microscopy, indicating that the polymorphonuclear cells decreased in the omentum and femur periosteum, but not in the subcutaneous. The implants adhered to the femur periosteum between the 7th and 30th postoperative days. The periosteum thickness decreased on the 7th postoperative day. The vascularization decreased on all the postoperative days. In the femur periosteum, vascularization increased between the 7th and 21st. Calcium deposition in the omentum and femur periosteum was verified from the 7th day, without difference on later days. Subcutaneously, calcium deposition areas increased along time. By scanning electron microscopy was detected calcium and phosphorus deposition from the 7th day. Subcutaneous aggregation of these minerals became more evident on the 15th and 30th day, but the difference was not significant in the other intracorporeal sites. Subcutaneously, mineral organization was greater on the 15th postoperative day. In the omentum and femur periosteum, there was no difference along time. In conclusion, the implant did not display hepatotoxicity, nephrotoxicity, or genotoxicity, and stimulated deposition, aggregation, and organization of bone precursors from the very 7th postoperative day, which suggested that they have osteogenic and osteoinductive potential.