Dynamic mechanical properties of gamma sterilized bovine cortical bone soaked in olive leaves extract

Abstract Terminal sterilization is necessary for bone grafts to prevent infection and disease transmission. Gamma radiation sterilization is currently the accepted method for its convenience and effectiveness in establishing the sterility of bone grafts. Unfortunately, the mechanical properties of bone grafts are also impaired during the gamma radiation sterilization process. Many studies addressed this problem by confining the free radical damage pathway to the bone collagen phase by using free radical scavengers. However, the safety of these free radical scavengers needs to be more carefully investigated before being applied in bone sterilization. Due to the abundance of phenolic compounds in olive leaves and the fact that these compounds are known to be powerful antioxidants, the aim of this study is to examine olive leaves extract (OLE) as a novel, affordable and non-toxic free radical scavenger for bone specimen protection during gamma radiation sterilization. The radioprotective effect of OLE on bone was investigated qualitatively by the dynamic mechanical analysis (DMA) technique. Specimens from the bovine femur were cut, and they were then soaked in previously prepared OLE for 4 days, 7 days, and 10 days at 4°C before being gamma sterilized with 25 KGy. In a 3-point bending configuration, the dynamic mechanical analysis was conducted at 1 Hz in the temperature range of 28–200°C. The research showed that gamma irradiation deteriorates the dynamic mechanical properties of bones. Statistically significant differences (p < 0.0001) in storage and loss moduli were observed between the irradiated group with 25 KGy and those pretreated by soaking in OLE before irradiation. The results obtained from this study proved that the use of OLE as a free radical scavenger before gamma sterilization would allow for biomechanically more stable bone grafts after implementation, and this finding is of great implication in bone banking.