title: Repeated irradiation from micro-computed tomography scanning at 2, 4 and 6 months of age does not induce damage to tibial bone microstructure in male and female CD-1 mice.
abstract: Long-term effects of repeated in vivomicro-computed tomography (μCT) scanning at key stages of growth and bone development (ages 2, 4 and 6 months) on trabecular and cortical bone structure, as well as developmental patterns, have not been studied. We determined the effect of repetitive μCT scanning at age 2, 4 and 6 months on tibia bone structure of male and female CD-1 mice and characterized developmental changes. At 2, 4 and 6 months of age, right tibias were scanned usingin vivoμCT (Skyscan 1176) at one of three doses of radiation per scan: 222, 261 or 460 mGy. Left tibias of the same mice were scanned only at 6 months to serve as non-irradiated controls to determine whether recurrent radiation exposure alters trabecular and cortical bone structure at the proximal tibia. In males, eccentricity was lower (P<0.05) in irradiated compared with non-irradiated tibias (222 mGy group). Within each sex, all other structural outcomes were similar between irradiated and non-irradiated tibias regardless of dose. Trabecular bone loss occurred in all mice due to age while cortical development continued to age 6 months. In conclusion, repetitive μCT scans at various radiation doses did not damage trabecular or cortical bone structure of proximal tibia in male and female CD-1 mice. Moreover, scanning at 2, 4 and 6 months of age highlight the different developmental time course between trabecular and cortical bone. These scanning protocols can be used to investigate longitudinal responses of bone structures to an intervention.
authors.affiliation: Department of Kinesiology, Faculty of Applied Health Sciences, Brock University, St Catharines, Ontario, Canada; Centre for Bone and Muscle Health, Brock University, St Catharines, Ontario, Canada.
authors.forename: Sandra M
authors.initials: SM
authors.lastname: Sacco
authors.affiliation: Centre for Bone and Muscle Health, Brock University, St Catharines, Ontario, Canada; Department of Health Sciences, Faculty of Applied Health Sciences, Brock University, St Catharines, Ontario, Canada.
authors.forename: Caitlin
authors.initials: C
authors.lastname: Saint
authors.affiliation: Department of Kinesiology, Faculty of Applied Health Sciences, Brock University, St Catharines, Ontario, Canada; Centre for Bone and Muscle Health, Brock University, St Catharines, Ontario, Canada.
authors.forename: Amanda B
authors.initials: AB
authors.lastname: Longo
authors.affiliation: Department of Kinesiology, Faculty of Applied Health Sciences, Brock University, St Catharines, Ontario, Canada; Centre for Bone and Muscle Health, Brock University, St Catharines, Ontario, Canada.
authors.forename: Charles B
authors.initials: CB
authors.lastname: Wakefield
authors.affiliation: Bruker-microCT , Kontich, Belgium.
authors.forename: Phil L
authors.initials: PL
authors.lastname: Salmon
authors.affiliation: Centre for Bone and Muscle Health, Brock University, St Catharines, Ontario, Canada; Department of Health Sciences, Faculty of Applied Health Sciences, Brock University, St Catharines, Ontario, Canada.
authors.forename: Paul J
authors.initials: PJ
authors.lastname: LeBlanc
authors.affiliation: Department of Kinesiology, Faculty of Applied Health Sciences, Brock University, St Catharines, Ontario, Canada; Centre for Bone and Muscle Health, Brock University, St Catharines, Ontario, Canada; Department of Health Sciences, Faculty of Applied Health Sciences, Brock University, St Catharines, Ontario, Canada.
authors.forename: Wendy E
authors.initials: WE
authors.lastname: Ward