Tehran University of Medical Sciences Acta Medica Iranica 0044-6025 52 3 2014 03 15 215 219 Babak Arjmand Chronic Diseases Research Center, Endocrinology and Metabolism Research Institute, Tehran University of Medical Sciences, Tehran, Iran. AND Brain and Spinal Cord Injury Research Center, Tehran University of Medical Sciences, Tehran, Iran. Hamid Reza Aghayan Chronic Diseases Research Center, Endocrinology and Metabolism Research Institute, Tehran University of Medical Sciences, Tehran, Iran. AND Brain and Spinal Cord Injury Research Center, Tehran University of Medical Sciences, Tehran, Iran. Bagher Larijani Endocrinology and Metabolism Research Center, Endocrinology and Metabolism Research Institute, Tehran University of Medical Sciences, Tehran, Iran. Mehrnaz Sahebjam Brain and Spinal Cord Injury Research Center, Tehran University of Medical Sciences, Tehran, Iran. Firoozeh Ghaderi Brain and Spinal Cord Injury Research Center, Tehran University of Medical Sciences, Tehran, Iran. Parisa Goodarzi Brain and Spinal Cord Injury Research Center, Tehran University of Medical Sciences, Tehran, Iran. AND Cellul Fanavaran Knowledge-Based Organization, Tehran University of Medical Sciences, Tehran, Iran. 2015 10 11 The gamma irradiation has been used for end sterilization of allograft bones and its effects with a 25 kGy dosage on the osteoinductive properties of demineralized bone allograft powder was studied. This work carried out using an experimental method in an animal model. In this study the demineralized bone allograft powder which had been sterilized and prepared with gamma irradiation in a 25 kGy dosage in 18 hours, was used as a study group and the demineralized bone allograft powder which had been prepared aseptically was used as the reference group. 30 mg of bone powder from each group were implanted into right and left paravertebral muscles of eighteen rats, separately. After four weeks, the implanted samples were harvested with a 0.5 cm border and then the osteoinductivity of implants in two groups were compared with histopathologic studies. In 94.4% of the reference samples a new bone formation was observed. In the study group, this difference was observed only in 27.7% of samples (P<0.002). It appears that using gamma irradiation may lead to a reduction in osteoinduction properties of demineralized bone allograft powder. https://acta.tums.ac.ir/index.php/acta/article/view/4671 https://acta.tums.ac.ir/index.php/acta/article/download/4671/4331