Journal of bone and mineral research : the official journal of the American Society for Bone and Mineral Research
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J. Bone Miner. Res. · Jun 2007
Optimal timing of a single dose of zoledronic acid to increase strength in rat fracture repair.
We hypothesized that ZA treatment would bolster fracture repair. In a rat model for closed fracture healing, a single dose of ZA at 0, 1, or 2 wk after fracture significantly increased BMC and strength of the healed fracture. Delaying the dose (1 or 2 wk after fracture) displayed superior results compared with dosing at the time of fracture. ⋯ The timing of a single systemic dose of ZA plays an important role in the modulation of callus properties in this rat fracture model; delaying the single dose produces a larger and stronger callus.
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J. Bone Miner. Res. · Jun 2007
Thyroid-stimulating hormone restores bone volume, microarchitecture, and strength in aged ovariectomized rats.
We show the systemic administration of low levels of TSH increases bone volume and improves bone microarchitecture and strength in aged OVX rats. TSH's actions are mediated by its inhibitory effects on RANKL-induced osteoclast formation and bone resorption coupled with stimulatory effects on osteoblast differentiation and bone formation, suggesting TSH directly affects bone remodeling in vivo. ⋯ These results show for the first time that systemically administered TSH prevents bone loss and restores bone mass in aged OVX rats through both antiresorptive and anabolic effects on bone remodeling.