Quantitative and Qualitative Analyses of Low-mineral-diet Ovariectomised Rat Femora Using Microscopic Computed Tomography

Abstract

The aim of this study was to monitor changes in bone density and bone quality (microarchitecture) in the femoral epiphyseal region in rats with bone loss induced by oestrogen deficiency and accelerated by mineral deficiency. Forty-eight Wistar rats were divided into 3 groups (n = 16 per group): Group 1, sham-operated rats on a normal diet; Group 2, ovariectomised rats on a normal diet; and Group 3, ovariectomised rats on a mineral-deficient diet. Observations were conducted 4, 8, 16, and 24 weeks after the operation (sham or ovariectomy), while the rats were on their respective diets. Microscopic computed tomography of the femoral epiphyseal region was used to generate 3-dimensional bone density distribution maps, and to compute bone density values. Densities of cortical and cancellous bone in Groups 2 and 3 were significantly less than densities in Group 1, and densities in Group 3 were significantly less than densities in Group 2 at nearly every post-operative time interval.
This study demonstrated that: a) ovariectomy in rats induces bone loss; b) a mineral-deficient diet accelerates bone loss that has been induced by oestrogen deficiency; and c) 3-dimensional bone density distribution maps may be useful in diagnosing osteoporosis and other diseases causing bone loss. Microscopic computed tomography is a powerful analytical tool for measuring spatial variations in bone density, and temporal changes in the patterns of 3-dimensional bone density distribution maps.