ETHYLENE-OXIDE DOES NOT EXTINGUISH THE OSTEOINDUCTIVE CAPACITY OF DEMINERALIZED BONE - A REAPPRAISAL IN RATS

We examined the influence of ethylene oxide (EO) and gamma irradiation on the osteoinductive capacity of demineralized bone. Demineralized b one powder prepared from Wistar rats was exposed to EO (55 degrees C o r 40 degrees C) or gamma irradiation (25 KGy) or was preserved in etha nol, Sterilely-prepared bones sewed as controls. The powder was packed in a gelatin capsule and implanted for 6 weeks in muscles of 6-week-o ld female rats. Exposure of demineralized bone particles to EO 55 degr ees G resulted in an almost complete loss of osteoinductivity. Irradia ted bones lost about 40% of their osteoinductive capacity, while steri lization with EO at 40 degrees C resulted in only a slight alteration of the osteoinductivity, as assessed by the recovered weight ratio, ca lcium content, alkaline phosphatase activity measurements and histomor phometry. Ethanol treatment had no influence on the new bone yield whe n compared to controls. As EO exposure at 40 degrees C is a true steri lization procedure, it can be recommended in a clinical setting for it s small effect on osteoinductive capacity as assessed experimentally i n rats.