Fourier-Transform Raman Spectroscopy Study of the Ovariectomized Rat Model of Osteoporosis

The ovariectomized rat model of osteoporosis was studied using FT-Raman spectroscopy on the surface of sitespecific bones. Twelve, 3 month old female Wistar rats (230 ± 10 g) were divided into two groups (n = 6 per group), one group was: ovariectomized (OVX) and the other sham-operated (SHAM). The rats were sacrificed to collect samples twelve weeks after the surgical operation. The right femur and tibia as well as the third lumbar vertebra were harvested and subjected to FT-Raman analysis on the following bones sites: femoral neck (FN), femoral mid-shaft (FS), proximal tibial metaphysis (PTM), tibial mid-shaft (TS), and lumbar vertebral body (LVB). Analysis of individual Raman peaks showed site-dependent variations in the bone: the ovariectomy induced lower mineral content (959 cm -1 ) in trabecular bone sites (FN, PTM and LVB) and higher matrix content (1265 and 1665 cm -1 ) in cortical bone sites (FS and TS). In addition, a lower mineral to matrix ratio and a higher carbonate/phosphate were observed in the OVX group, which indicated a change in bone chemical content and some degree of remodeling specially in the trabecular bone sites. These data support the hypothesis that FT-Raman spectroscopy can be used to evaluate the bone alterations induced by this experimental model.