Erschienen in:
01.01.2012 | Original Research
Skeletal Remodeling Following Clinically Relevant Radiation-Induced Bone Damage Treated with Zoledronic Acid
verfasst von:
Susanta K. Hui, Gregory R. Fairchild, Louis S. Kidder, Manju Sharma, Maryka Bhattacharya, Scott Jackson, Chap Le, Douglas Yee
Erschienen in:
Calcified Tissue International
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Ausgabe 1/2012
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Abstract
Our aim was to determine if zoledronic acid (ZA) changes 45Ca pharmacokinetics and bone microstructure in irradiated, ovary-intact (I) and irradiated, ovariectomized mice (OVX), two groups with different patterns of skeletal damage. The hind limbs of I and OVX BALB/c mice received a single 16-Gy radiation dose, simulating pre- and postmenopausal female cancer patients undergoing radiation treatment. All I and OVX mice were radiolabeled with 15 μCi 45Ca. Mice were treated with or without a 0.5 mg/kg injection of ZA. The time course of bone mineral remodeling was evaluated using a fecal 45Ca assay, measured by liquid scintillation. A group of nonirradiated, intact mice were used for the longitudinal evaluation of 45Ca biodistribution. Distal femur bone histomorphometric parameters were measured using microCT at 50 days post–ZA intervention. Most 45Ca was incorporated into the skeleton and eliminated from the soft tissues within 3–5 days postirradiation, attaining a steady state of excretion at 25–30 days. ZA intervention in both groups resulted in a rapid decrease in fecal 45Ca excretion. There was a significant difference in 45Ca excretion in the OVX ± ZA (P = 0.005) group but not in the I ± ZA (P = 0.655) group. The rate of excretion of fecal 45Ca was slower in the OVX + ZA compared to the I + ZA group (P = 0.064). 45Ca assay is useful to monitor the time course of bone mineral remodeling after an antiresorptive intervention in irradiated mice, providing a basis to investigate bone effects of cancer therapy protocols. For equivalent doses of ZA, recovery may depend on the nature and degree of skeletal damage.