Acute lymphoblastic leukemia (ALL) survivors experience chronic health conditions from treatment, including osteoporosis. ALL radiation therapy is known to induce bone resorption, but animal models for this loss do not exist.

Five-week-old C57Bl/6 mice were either irradiated with 8 Gy X rays or kept as nonirradiated controls. Bones were collected at 2, 4, and 6 days post-irradiation. MicroCT and finite element analysis assessed microarchitectural and structural parameters. Serum osteocalcin and TRAP-5b levels were quantified.

At 2 days post-irradiation, osteocalcin and trabecular bone volume fraction (BV/TV) were elevated in irradiated mice compared to controls. By 6 days, BV/TV, connectivity density, and trabecular stiffness declined, while TRAP-5b levels and cortical volume and stiffness increased.

In conclusion, radiation exposure in young mice causes an acute increase in bone mass followed by rapid loss. This suggests less than a one-week window after irradiation to prevent or mitigate bone loss due to radiation therapy.