Body mass composition

We performed dual X-ray absorptiometry (DEXA) imaging to measure mouse adiposity. We performed a longitudinal assessment of 10 WT and 10 Lgals3^−/− mice; we first tested mice at 2–3 months old, followed by repeat assessment at 6–7 months old. Investigators were not blinded to mouse genotype. Mice received DEXA imaging in a random manner. DEXA testing occurred between 10:00 and 16:00. Animals were lightly anesthetized with isoflurane at 1–3 vol%, and imaged with a Piximus I (Inside/Outside, Fitchburg WI). Before data acquisition, the system was calibrated by imaging a phantom with defined radiological characteristics. We used vendor supplied software (Piximus I, GE Lunar) to identify regions of interest (ROIs) encompassing the mouse chest/abdomen/pelvis for determination of bone mass density (BMD), bone mineral content (BMC), bone area (BArea), tissue area (TArea), ratio of soft tissue attenuation (R_ST), total tissue mass (TTM), and percent adiposity (% fat). Data was analyzed by repeated measures analysis of variance (ANOVA, implemented in MATLAB 2011b) with genotype and mouse age as primary factors, and a genotype × age interaction.