Structure Model Index Changes in the Femoral Epiphyseal Region on Micro-Computed Tomography Caused by a Supplement Diet in Ovariectomized Rats

Abstract

We have developed a novel supplement diet for osteoporosis prevention that contains fructo- oligosaccharide, isoflavone, and calcium citrate, in addition to calcium phosphate (high mineral diet: HMD). The present study aimed to clarify whether rats with osteoporosis fed an HMD showed an improved structure model index (SMI) in the femoral epiphyseal region compared with rats fed a normal mineral diet (NMD). The experiment used 20-week-old ovariectomized rats divided into an NMD group (n=6) and an HMD group (n=6).� After 24 weeks on the diet, this study examined the changes in SMI and the 3-dimensional pseudocolor map (3D-map) using micro-computed tomography. Compared to the NMD group, the HMD group had significantly greater Trabecular Thickness (Tb. Th) and Trabecular Number, and shorter Trabecular Separation and Trabecular Spacing, indicating highly dense trabeculae. The trabeculae of the NMD group had low Tb. Th and bone volume / tissue volume (BV/TV), indicating a thin, rod-like shape, but the trabeculae of the HMD group had significantly greater Tb. Th and BV/TV, demonstrating a thick, plate-like structure. In the sagittal section image of the 3D-map, the trabecular bone of the NMD group showed low bone mineral density (BMD), represented by light blue and purple colors, on the growth plate side of the inner portion of the cortical bone, indicating near complete resorption of the trabecular bone. The trabecular bone of the HMD group showed moderate to low BMD, represented by light blue and green colors, on the growth plate side, indicating a greater trabecular bone density compared to the NMD group. The present results showed that the intake of HMD, compared to NMD, maintains the trabecular structure by preventing trabecular bone resorption, indicating the usefulness of HMD intake.