EFFECT OF STERILIZATION ON BONE MORPHOGENETIC PROTEIN

Demineralized bone matrix and bone morphogenetic protein have been use d clinically to accelerate bone regeneration. However, the best method of sterilization has been the subject, bf controversy. Some investiga tors have used ethylene oxide, but others have reported that; doses ad equate for sterilization destroyed the osteoinductivity of demineraliz ed bone matrix and that gamma irradiation was less harmful in this res pect. We used partially purified bone morphogenetic protein and type-I collagen to investigate the effects of sterilization by ethylene oxid e and gamma irradiation on the activity of bone morphogenetic protein. Osteoinductivity was reduced considerably after sterilization by gamm a irradiation at 2.5 Mrad and by ethylene oxide at 37 degrees C for 4 hours and at 55 degrees C for 1 hour; however, the reduction induced b y ethylene oxide at 29 degrees C for 5 hours was about half of the con trol values. This study showed that ethylene oxide at 29 degrees C for 5 hours can be used clinically for sterilization of bone morphogeneti c protein. We also investigated the effect of gamma irradiation on bon e morphogenetic protein and the collagen carrier separately and found that collagen was far more labile than bone morphogenetic protein.