Short-term and long-term effects of osteoporosis on incisor teeth and femoral bones evaluated by Raman spectroscopy and energy dispersive X-ray analysis in ovariectomized rats

Abstract

There are few published data on the relationship between loss of bone mass due to osteoporosis and poor tooth quality. This study analyzed the effects of osteoporosis on incisor teeth and femoral bones using optical techniques in rats. Twenty female Wistar rats aged 6months (n=20) were randomized into two groups: control group, non-ovariectomized rats (n=10); ovariectomy group, ovariectomized rats to induce osteoporosis (n=10). Each group was subdivided randomly into two groups containing five rats each as follows. Control group 1: non-ovariectomized rats euthanized at the age of 9 or 3months post-ovariectomy (n=5); Control group 2: non-ovariectomized rats euthanized at the age of 1year or 6months post-ovariectomy (n=5); ovariectomy group 1: ovariectomized rats euthanized at the age of 9months or 3months post-ovariectomy (n=5); ovariectomy group 2: ovariectomized rats euthanized at the age of 1year or 6months post-ovariectomy (n=5). The incisor teeth and femoral bones of Wistar rats were removed to perform Raman spectroscopy using an excitation laser at 785nm. In addition, an energy-dispersive X-ray spectrometer system was used to evaluate calcium (Ca) and phosphorus (P). The main findings included significant changes (p<0.05) for phosphate and carbonate band areas for both incisor teeth and femur bones. In addition, there was significant negative correlation between the P concentration and phosphate/carbonate ratio (lower P content-larger ratio, p<0.05) for incisor teeth and femoral bones. The proline and CH2 wag band areas were significantly reduced only for the incisor teeth (p<0.05). Therefore, Raman spectroscopy assessed the compositional, physicochemical and structural changes in hard tissue. The current study also pointed out the possible action mechanisms of these changes, bone fracture risk and dental fragility. It is important to emphasize that poor dental quality may also occur due to osteoporosis.