Bone microstructure in OVX and normal rat bone as revealed by confocal and electron microscopy

In our recent work we observed that the microstructure of the osteocyte lacunar-canalicular system is quite extensive, raising the possibility that the interstitial fluid porosity might have been previously underestimated. In this study we employed an ovariectomized (OVX) rat model to determine the effect of osteoporosis on interstitial fluid porosity. Bone sections were visualized using confocal and electron microscopy. Even though no statistical difference was found between the OVX and normal bone porosities, the total cortical porosity measured (∼ 20%) was greater than values previously reported (∼ 9%), the difference due to the complexity of the lacunar-canalicular network. Moreover, the analysis of tibial sections using electron microscopy revealed a pattern of higher mineralization in areas of low lacunar-canalicular porosity. More extensive studies involving the quantification of porosity in different cortical bone locations and especially of cancellous bone porosity are necessary to further investigate the effect of osteoporosis on bone’s interstitial fluid pathway.