Dose‐dependent response of gamma irradiation on mechanical properties and related biochemical composition of goat bone‐patellar tendon‐bone allografts

Abstract

We studied the effects of gamma irradiation on the dimensions, mechanical and material properties, and mature hydroxypyridinium crosslink density of collagen in goat patellar tendon-bone specimens. Left and right patellar tendon-bone units were removed from 10 adult female goats and were bisected longitudinally. Each tendon half was frozen, and then the left halves were exposed to 4, 6, or 8 Mrad (40,000, 60,000, or 80,000 Gy) of gamma irradiation. The contralateral tendon halves served as controls (no irradiation). Each specimen then was loaded to failure in tension, and its soft-tissue midsubstance was processed to measure collagen content and hydroxypyridinium crosslink density. Dose-dependent reductions in the mechanical properties were found, including 46% (p < 0.01) and 18% (p < 0.05) reductions in maximum force and stiffness, respectively, at 4 Mrad. Similar reductions were noted in material properties, including 37% (p < 0.005) and 8% (p > 0.05) reductions in maximum stress and modulus, respectively, at 4 Mrad. These results are consistent with our previous report involving 2 and 3 Mrad (20,000 and 30,000 Gy) of exposure. We also found significant decreases in hydroxypyridinium crosslink density with 6 Mrad of irradiation (p < 0.05). However, since only one biomechanical parameter (modulus) correlated significantly with only one biochemical measure (hydroxypyridinium crosslink density) (p < 0.05), other possible mechanisms also are being explored to more fully explain these dose-dependent changes.

On the effect of X-ray irradiation on the deformation and fracture behavior of human cortical bone

“…3a). These observations are consistent with reports [6,[8][9][10]12,13,19] of the significant effect of gamma irradiation on the plastic properties such as the bending strength and toughness, rather than the elastic properties such as stiffness and elastic limit. Of importance is that although the irradiation doses in question are very large compared to the few second exposures typical of in situ x-ray scattering experiments, they are definitely comparable to the irradiation associated typical tomography imaging runs (Table 1),…”

“…At the high dose end (>10 kGy), gamma irradiation is commonly used to terminally sterilize allograft tissues and bones [2][3][4][5], and has been proven to be very potent sterilization agent with the ability to effectively penetrate tissue. However, gamma irradiation is also known to adversely affect the mechanical and biological properties of tissue in a dose-dependent manner by degrading the collagen [6][7][8][9][10][11][12][13][14]. Specifically, gamma rays split polypeptide chains; in wet specimens, irradiation causes release of free radicals via radiolysis of water molecules that induces cross-linking reactions in collagen molecules [15][16][17].…”

The Assessment as Bone Mineral Density of Bone Damage in Radiology Workers Occupationally Exposed to Ionizing Radiation

“…Regarding published reports ionizing radiation has harmful biological effects on living organisms and this effects increase depending on radiation dose and exposure time to radiation (9,(13)(14)(15)(16). In addition, our study shows that depending on radiation exposure, bone mineral density decreases significantly of all radiology workers compared to control group.…”

Gamma Radiation Sterilization Reduces the High-cycle Fatigue Life of Allograft Bone

“…Gamma radiation sterilization is the current standard given its convenience and efficacy in achieving sterility and the response toward HIV and hepatitis C [12,14]. Unfortunately, the sterilization process by gamma radiation also impairs the mechanical properties of allografts owing to the scission of collagen molecules in the bone tissue [3,10,19,34,60].…”