The peripheral quantitative computed tomographic and densitometric analysis of skeletal tissue in male Wistar rats after chromium sulfate treatment

INTRODUCTION

This study evaluates the effects of three different doses of chromium sulphate on bone density and the tomographic parameters of skeletal tissue of rats.

MATERIAL AND METHODS

The experiment was performed on 40 male Wistar rats which received, by gavage, during 90 days, a chromium sulphate in either a daily dose of 400, 600 or 800 µg/kg BW. At the end of experiment, the rats were scanned using the densitometry method (DXA) to determine the bone mineral density, bone mineral content of total skeleton and vertebral column (L2-L4) and parameters of body composition (Lean Mass and Fat Mass). The isolated femora were scanned using peripheral a quantitative computed tomography method (pQCT) for a separate analysis of the trabecular and cortical bone tissue. The ultimate strength, work to ultimate and the Young modulus of femora was also investigated by the three-point bending test.

RESULTS

The negative impact of chromium was observed in relation to bone tissue. All doses significantly decreased total skeleton density and mineral content, and also had impact upon the isolated femora and vertebral column. Trabecular volumetric bone mineral density and trabecular bone mineral content measured by pQCT in distal femur metaphysis were significantly lower in the experimental groups than in the control. Higher doses of chromium also significantly decreased values of ultimate strength and Young modulus in the investigated femora.

CONCLUSIONS

The results of the experiment demonstrate that chromium sulphate is dose dependent, and exerts a disadvantageous effect on the skeleton, as it decreases bone density and resistance.

Maternal beef and postweaning herring diets increase bone mineral density and strength in mouse offspring

The maternal diet during gestation and lactation affects the long-term health of the offspring. We sought to determine whether maternal and postweaning crossover isocaloric diets based on fish or meat affect the geometry, mineral density, and biomechanical properties of bone in mouse offspring in adulthood. During gestation and lactation, C57BL/6 dams were fed a herring- or beef-based diet. After weaning, half of the pups in each group were fed the same diet as their dams, and half were fed the other diet. Areal bone mineral density (aBMD) and bone mineral content (BMC) of the whole body and lumbar spine were measured in the offspring by dual X-ray absorptiometry at 9 and 21 weeks of age. At 22-26 weeks, tibia bone geometry (length, cortical volumetric (v) BMD, BMC, area and thickness) was analyzed by peripheral quantitative computed tomography, and the biomechanical properties of the tibia were analyzed by the three-point bending test. Plasma insulin-like growth factor-1 was analyzed at 12 weeks. In comparison to the maternal herring diet, the maternal beef diet increased aBMD and BMC in the whole body and lumbar spine of adult offspring, as well as cortical vBMD, BMC, bone area, and thickness at the mid-diaphyseal region of the tibia and the biomechanical properties of tibia strength. In contrast, a postweaning beef diet decreased aBMD in the lumbar spine and BMC in the whole body and lumbar spine compared with a postweaning herring diet, which instead increased plasma insulin-like growth factor-1 levels. The change from a maternal beef diet before weaning to a herring diet after weaning decreased body weight and increased the cortical area, vBMD, BMC, thickness, and strength of the tibia. These significant crossover effects indicate that a preweaning maternal beef diet and a postweaning herring diet are optimal for increasing BMC and bone strength in offspring in adulthood.