Echo mri whole body composition analyzer

Body weight and food were measured before and 24 h after icv saline or BDNF injections. Food intake was calculated by subtracting the weights of food after 24 h from the starting weights and correcting for spillage. Body composition, i.e., fat mass and lean mass, of conscious rats was assessed using an EchoMRI whole-body composition analyzer (EchoMedical Systems, Houston, TX, USA) before and 24 h after icv saline or BDNF injections in the first cohort of rats.

Measures of energy balance and fuel utilization were performed as described in previous reports^{19 (link),20 (link)}. For measurements of energy balance, mice were acclimatized to the Colorado Nutrition Obesity Research Center animal satellite facility for several days before being placed in the eight-chamber metabolic monitoring system (Oxymax CLAMS- 8 M; Columbus Instruments). All mice remained in the chambers for 7 days, with at least 2 days of acclimatization to the new environment and at least 3 days for measurements of energy intake and expenditure. Twenty four hour urine was collected in the chambers, and urinary urea nitrogen, and creatinine were determined (ThermoElectron, Melbourne, Australia). Metabolic rate (MR) was measured every 16 min and calculated with the Weir equation (MR = 3.941 × vO2 + 1.106 × vCO2 − 2.17 × N), where N = urinary nitrogen^{21 (link)}. MR averaged over the day was then extrapolated throughout the 24 h testing period to acquire estimates of total energy expenditure (TEE) described previously^{19 (link)}. Body composition was determined in dams, litters, and adult offspring by quantitative magnetic resonance (qMR; Echo MRI Whole Body Composition Analyzer; Echo Medical Systems, Houston, TX, USA).

Body weight and body composition (total lean mass, total fat mass) were recorded weekly from week three and four. Body composition was measured using EchoMRI whole-body composition analyzer (Echo Medical Systems, Houston, TX, USA). At ten weeks blood glucose levels were measured prior to dissection after 2 hours of fasting using a glucometer (Contour, Bayer, Leverkusen, Germany). Liver triglycerides and proteins were measured in homogenized liver samples by commercially available kits (DC Protein Assay, Bio-Rad, München, Germany; TRIGS Triglycerides Assay, Randox, Crumlin, United Kingdom). For test statistics between the matBFMI and patBFMI, we applied a linear model using anova in R. Since litter size had a significant effect on all traits, phenotypic values were adjusted for litter size before statistic tests were performed, except for blood glucose and liver triglycerides.