Figure 6.

Differences in Raman properties between tissue sites and with age. Raman spectra were collected from the inner cortex (2 sites within black box) and the outer lamellae near the periosteum (2 sites within blue box with dashed lines) for one quadrant of the embedded tibia cross-section (a). The inner tissue had a higher mineral-to-matrix ratio (MMR) than the outer tissue at 6-mo. and at 12-mo. but not 24-mo. of age (b). When the MMR was determined by a less organizational-sensitive peak ratio, there were no differences in mineralization between sites or with age (c). There was more carbonate in the mineral lattice of bone from 24-mo. rats than from younger rats (d). Surprisingly, crystallinity was lowest at 12-mo. for both tissue sites of the anterior cortex (e). *p<0.05 vs. 6-mo. and ^#p<0.05 vs. 12-mo. p-value is given for inner region vs. outer lamellae.