Animal Physiology Core

The Core uses a Sable Systems Promethion Core High-Definition Metabolic Phenotyping System for metabolic studies in mice. The system accommodates 16 mice housed in home caging and allows for measurement of energy expenditure, oxygen (O₂) consumption, carbon dioxide (CO₂) production, respiratory exchange ratio, heat generation calculated from gas exchange data, food and water consumption, locomotor activity, and voluntary wheel activity. The environmental sensor array captures 6 different parameters at once: humidity, barometric pressure, temperature, light, motion, and sound. The Stable Isotope Gas Analyzer continuously measures ¹³C and ¹⁸O isotopes in exhaled breath and allows the study of whole-body oxidation of endogenous and exogenous nutrients. The system is also compatible with a mouse treadmill that enables measurement of oxygen consumption during exercise. The Promethion data analysis software package, ExpeData, allows the user to explore acquired data where each parameter of the system has been recorded once per second, enabling real-time analysis or for comparison to previous research.

The Core's iNSiGHT Dual Energy X-ray Absorptiometry instrument uses X-ray to assess lean and fat mass distribution, bone mineral density and bone length in mice and rats. Body composition  can be performed on animals up to 250 grams in weight. Analysis of the body scan is performed on defined regions of interest as indicated by the researcher. Total body, interscapular, abdominal, visceral and subcutaneous compartments can be measured for fat and lean mass. The length of major bones, including spinal cord, tibia and femur, can be measured using calibrated calipers.

A non-invasive tail-cuff sensor and monitoring system is used for the measurement of systolic and diastolic blood pressure and heart rate. Mice are measured with a system from Visitech Systems (BP-2000a), which can accommodate four mice for simultaneous measurement. Animals are acclimated to the devices during two consecutive days, with measurements conducted on day three..

To evaluate the impact of single bouts of exercise and exercise training, the Core maintains and instructs users on experimental design and proper use of 5-lane treadmills (3 stand alone, 1 with Promethion system) with adjustable speed and grade that accommodate mice or rats. For voluntary exercise training studies, the Core has 58 cage systems with running wheels that allow for mice or rats to voluntarily exercise, including 16 Columbus Instruments Mouse Home Cage Running Wheels. In addition, users can be trained on the Columbus Instruments Grip Strength Meter to assess forelimb muscle strength and neuromuscular function by sensing the peak force an animal applies in grasping specially designed pull bar assemblies.

Four Caron Diurnal Incubators (Model 7000-33) allow for more than one temperature study to be run simultaneously. These incubators can house animal cages at temperatures ranging from 5 degrees Celsius to 30 degrees Celsius. Light cycles can also be adjusted for studies using a 12-hour light/dark cycle or other lighting conditions. Two incubators will be housed in the Joslin Animal Facility at CLS8, and the other two will be housed in the APC at Dana 6. Maintaining incubators in both locations will improve user access and reduce the need to transfer mice between facilities.

An IVIS Spectrum micro CT imaging system (Caliper/Perkin Elmer) uses novel optical imaging technology to facilitate non-invasive longitudinal monitoring of disease progression, cell trafficking and regulated gene expression patterns in living animals via bioluminescent and/or fluorescent reporters. In addition, microCT generated 3D tomography can be measured simultaneously for anatomical context.

The APC staff train users in oral and intraperitoneal glucose tolerance tests (OGTT/IPGTT) and insulin tolerance tests (ITT) using validated protocols. Testing is performed in the dedicated procedure rooms at the Dana 6 APC facility or the CLS 8 barrier facility.

The APC staff train users in the use of metabolic cages that precisely measure food and water intake and provide uncontaminated separation of urine and feces from mice, ensuring high sample purity.