Mineral to matrix ratio determines biomaterial and biomechanical properties of rat femur : application of Fourier transform infrared spectroscopy

We studied the changes of biomaterial and biomechanical properties of the rat
femur during development. Thirty male Wistar rats were allocated to 6 groups : aged 6
weeks (n=5), 9 weeks (n=5), 12 weeks (n=5), 15 weeks (n=5), 24 weeks (n=5), and 36 weeks
(n=5). The mineral to matrix ratio (M/M ratio) of rat femur by Fourier transform infrared
spectroscopy was 0.97 0.10 at the age of 6 weeks, and reached the maximum of 1.52
0.17 at the age of 36 weeks. Total bone mineral density (BMD) by peripheral quantitative
computed tomography of the femoral shaft aged 6 weeks was 479.1 58.7 mg/cm3, and
reached the maximum of 1022.2 42.3 mg/cm3 at the age of 36 weeks. The ultimate load to
failure of the femur of the rat aged 6 weeks by the three-point bending test was 29.6 6.1 N.
At the age of 36 weeks, the ultimate load to failure of the rat femur increased to the maximum
of 283.5 14.7 N. The results showed that the M/M ratio increased with development
as total BMD and bone strength increased. The results suggest that the M/M ratio is one
of the determinants of the biomaterial and biomechanical properties of bone.

The journal of medical investigation : http://medical.med.tokushima-u.ac.jp/jmi/index.html