Abstract
Objective of this study is to investigate whether diet or sex influences calcification of the tendon in the Mop-3/Bmal-1 gene knock-out mouse (Bmal-1 knock-out mouse) by comparing “in vivo” micro-computed tomography imaging, soft-tissue X-ray imaging, and histologic evaluation as the ‘gold standard’.
23 mice were placed into 8 groups according to genetic background, diet and sex. They underwent micro-CT imaging at magnifications of ×1.5, ×4.0, and ×10.0, and soft-tissue X-ray imaging. We compared 37 tendons in each of the 8 groups that showed calcification on micro-CT ×10.0 and on histologic evaluation.
On micro-CT×1.5 images, 8 of the 21 joints of Bmal-1 knock-out mice showed calcification, and calcification was seen on micro-CT×4.0 images in 19 of 21 joints, and on micro-CT ×10.0 and SOFTEX, calcifications were seen in 20 of the 21 joints. For detecting calcifications, the diagnostic accuracy of micro-CT×1.5 was 0.68, that of micro-CT ×4.0 was 0.97, that of micro-CT ×10.0 and SOFTEX was 1.00. Regarding sex and diet, calcification was seen in 5 of 5 joints from males fed a high-fat diet, 4 of 4 joints from females fed a high-fat diet, 5 of 5 joints from males fed a regular-fat diet, and 6 of 7 joints from females fed a regular-fat diet.
High-speed micro-CT ×10.0 gave good diagnostic results for calcifications. Neither diet nor sex affected the appearance of the joints, whether calcified or normal. Because high-speed micro-CT is rapid and limits the animal’s radiation dose, it may be an effective technique for in vivo research.
