Effect of Feeding Grapefruit Pulp on Bone Microarchitecture and Strength in Orchidectomized Rats

Abstract

The aim of this study was to evaluate the effects of enhancing antioxidant status on bone microarchitecture and strength in a male rat model of osteoporosis. Three month-old male Sprague-Dawley rats were randomly assigned to four groups. Three groups were orchidectomized (ORX) and one group had sham surgery (SHAM). Three days post-surgery, ORX rats were assigned to the following treatments: ORX, ORX + 5% grapefruit pulp and ORX + 10% grapefruit pulp. The rats were fed a semi-purified, powdered casein based diet modified from AIN-93M for 2 months. At the end of the study, blood and bones were collected. The bone samples were assessed for bone density and microarchitecture using DXA and microcomputed tomography. The data were analyzed using SAS (version 9.1) and the generalized linear model (GLM) and Least Significant Differences (LSD) procedures were used to separate treatment differences (p<0.05). Microarchitectural changes seen in tibia showed a marked improvement in the 10% grapefruit group in certain measures whilst none were seen in the 5% group. ORX negatively impacted certain measures of bone microarchitecture that included bone volume fraction, connectivity density, trabecular number and trabecular separation of the tibial bone. In 4th lumbar trabecular assessment, a dose dependent effect was seen as ORX + 10% grapefruit pulp rats had significantly improved bone volume fraction, connectivity density, trabecular number and reduced trabecular separation. FE analysis of the tibial bone showed that a greater force was required to compress SHAM than any of the ORX groups though no significant difference was appreciated in the lumbar vertebrae.