PLOS ONE | https://doi.org/10.1371/journal.pone.0174806 April 3, 2017

Volume 12, Issue 4, March 2017, Article number e0174806

Attenuating trabecular morphology associated with low magnesium diet evaluated using micro computed tomography 

Shu-Ju Tu1, Shun-Ping Wang2,3, Fu-Chou Cheng4, Chia-En Weng1, Wei-Tzu Huang1, Wei-Jeng Chang5, and Ying-Ju Chen6

1Department of Medical Imaging and Radiological Sciences, College of Medicine, Chang Gung University, Kwei-Shan, Tao-Yuan 333, Taiwan

2Department of Orthopedics, Taichung Veterans General Hospital, Taichung 407, Taiwan

3Department of Life Science, Tunghai University, Taichung 407, Taiwan

4Stem Cell Center, Department of Medical Research, Taichung Veterans General Hospital, Taichung 407, Taiwan

5National Laboratory Animal Center, National Applied Research Laboratories, Taipei 115, Taiwan

6Department of Food and Nutrition, Providence University, Taichung 433, Taiwan

 

Abstract

OBJECTIVE: The literature shows that bone mineral density (BMD) and the geometric architecture of trabecular bone in the femur may be affected by inadequate dietary intake of Mg. In this study, we used microcomputed tomography (micro-CT) to characterize and quantify the impact of a low-Mg diet on femoral trabecular bones in mice.

MATERIALS AND METHODS: Four-week-old C57BL/6J male mice were randomly assigned to 2 groups and supplied either a normal or low-Mg diet for 8weeks. Samples of plasma and urine were collected for biochemical analysis, and femur tissues were removed for micro-CT imaging. In addition to considering standard parameters, we regarded trabecular bone as a cylindrical rod and used computational algorithms for a technical assessment of the morphological characteristics of the bones. BMD (mg-HA/cm3) was obtained using a standard phantom.

RESULTS: We observed a decline in the total tissue volume, bone volume, percent bone volume, fractal dimension, number of trabecular segments, number of connecting nodes, bone mineral content (mg-HA), and BMD, as well as an increase in the structural model index and surface-area-to-volume ratio in low-Mg mice. Subsequently, we examined the distributions of the trabecular segment length and radius, and a series of specific local maximums were identified. The biochemical analysis revealed a 43% (96%) decrease in Mg and a 40% (71%) decrease in Ca in plasma (urine excretion).

CONCLUSIONS: This technical assessment performed using micro-CT revealed a lower population of femoral trabecular bones and a decrease in BMD at the distal metaphysis in the low-Mg mice. Examining the distributions of the length and radius of trabecular segments showed that the average length and radius of the trabecular segments in low-Mg mice are similar to those in normal mice.

PMID: 28369124

 

 

Summary

The quality of trabecular bones can be determined according to their BMD and architectural characteristics. Our technical assessment performed using micro-CT imaging quantitatively revealed a lower population of trabecular bones at the distalmetaphysis in mice that were supplied a low-Mg diet.Compared with mice that were supplied a basal diet, the low-Mg mice exhibited a decrease in the total tissue volume, trabecular bone volume, percent bone volume, fractal dimension, number of trabecular segments, trabecular segment density, number of connecting nodes, connecting node density, and BMC,as well as an increase in the structural model index and surface-area-to-volume ratio in the low-Mg mice.We also examined the distributions of the trabecular segment length and radius, which havenot been discussed in previous research. A global maximum of the trabecular segment length and a series of local maximums of the trabecular segment radius were identified in the present study. In our experiments, equal amounts of Ca were supplied to both groups. However, our biochemical analysis revealed lower concentrations of Ca in the plasma and urine of the low-Mg mice.Consequently, additional Ca may have been retained in the low-Mg mice.Our findings indicate that retention of Ca may be regulated by adjusting the amount of dietary Mg. Further study is required to clarify the physical and biological interactive mechanisms of Ca–Mg and the corresponding effect on bone growth.

 

 

(A) The growth plate was first located at the distal femur site as a reference plane and delineated a 2 mm distance along the longitudinal direction as shown in the red box for our region of interest.

(B) A 3-dimensional surface rendering figure of the whole femur bone which is reconstructed from micro CT images is shown.