Effects of gamma-ray irradiation on mechanical properties, osteoconductivity, and absorption of porous hydroxyapatite/collagen.
In this study, the effects of gamma-ray irradiation on the mechanical properties, absorbability, and osteoconductivity of porous hydroxyapatite/collagen (HAp/Col) were investigated. Porous HAp/Col was exposed to 16, 25, 35, or 50 kGy of gamma-ray irradiation. The compressive elastic modulus showed irradiation dose-dependence, with a particularly pronounced decrease in the 50-kGy treatment group. An in vitro enzymatic digestion test showed that gamma-ray irradiation of porous HAp/Col resulted in accelerated degradation by collagenase. For in vivo studies, porous HAp/Col was transplanted into the back muscles or bone defects in the femoral condyle of rats. Specimens were obtained at 2, 4, and 8 weeks postoperatively. Absorption of the implants in the muscle was time- and irradiation dose-dependent, with notable absorption for the 35- and 50-kGy groups at 2 weeks. At the skeletal sites, porous HAp/Col demonstrated high osteoconductivity in all irradiation treatment groups. Interestingly, not only implant absorption but also bone formation was irradiation dose-dependent at early time points.
Department of Orthopaedic and Spinal Surgery, Graduate School, Tokyo Medical and Dental University, Tokyo, Japan.
Yuichi
Y
Kawasaki
Shinichi
S
Sotome
Toshitaka
T
Yoshii
Ichiro
I
Torigoe
Hidetsugu
H
Maehara
Yumi
Y
Sugata
Masahiro
M
Hirano
Naomi
N
Mochizuki
Kenichi
K
Shinomiya
Atsushi
A
Okawa
D000042:Absorption; D000818:Animals; D018786:Bone Substitutes; D001842:Bone and Bones / Q000737:chemistry* / Q000528:radiation effects; D003094:Collagen / Q000737:chemistry*; D017886:Durapatite / Q000737:chemistry*; D005720:Gamma Rays; D008855:Microscopy, Electron, Scanning; D051381:Rats
D018786:Bone Substitutes; D003094:Collagen; D017886:Durapatite