Fourier transform infrared microscopic imaging: effects of estrogen and estrogen deficiency on fracture healing in rat femurs.

Infrared spectroscopic imaging with 6-10 microm spatial resolution was used to characterize the changes in fracture callus mineral content, carbonate content, mineral crystallinity, and collagen maturity in femurs of 3-month-old ovariectomized rats treated with estrogen (estrogen sufficiency) or vehicle (estrogen deficiency). Comparisons were also made in these animals to cortical bone at a distance from the callus. Analyses at 4, 8, and 12 weeks post fracture demonstrated that healing was accelerated in the estrogen-sufficient animals as demonstrated by increasing mineral content and collagen maturity and decreasing carbonate incorporation.