Rodent Physiology Lab
Rodent exercise laboratory research focuses on beneficial or detrimental impact of exercise in certain special animal's model conditions. Both rats and mice models are studied.
Rodent Physiology Lab (RPL) is the biological core facility of the group. The laboratory has two sub-cores: (I) Biological sub-Core and (II) Analytical sub-Core. Our main goal is to design and implement in vivo rodent experiments to investigate the effects of Loading/Unloading on muscle and whole-body physiology and intermediary metabolism.
The main product of the RPL Core labs is the generation of the biological data sets that reflect changes in muscle and whole-body physiology brought about by muscle Loading/Unloading. The Biological sub-Core lab is responsible for implementing in vivo experimentations. Data sets span across three biological levels: (I) whole-body, (II) organ and (III) cellular. An example of "whole-body" end-points would be body weight, food intake, VO2MAX and etc. For organ end-points, we use organ weights, composition, and turnover. For the cellular level, we measure metabolite concentrations (glucose, lactate, ATP, phosphocreatine and etc) and enzyme activities (hexokinase, lactate dehydrogenase, pyruvate kinase and etc).
Capabilities
The rodent exercise physiology lab (~ 250 sq ft) is fully equipped to study physiological and metabolic responses to exercise in rats and mice. The laboratory contains 1 motorized multiple lane treadmill for training and 2 fitted with a computerized metabolic analysis system (Columbus Instruments), blood gases and metabolites analyzer (ABL, Radiometer America), non-invasive tail blood pressure and hemodynamics analyzer (Kent Scientific) and blood flow analyzer (Transonic).
The Analytical sub-Core facility is responsible for animal handling, surgery, sample processing and analytical assays to yield biological data for mathematical modeling. The Analytical sub-Core facility is equipped with state-of-the-art equipment for most common biological assays using specrophotometry and luminescence. Also, we have access to Mass Spectrometry Core laboratory for GC/MS analyses.
Biological models/system
Loading is represented by exercise training. We use two modes of exercise: Aerobic and Resistance. For Aerobic exercise, we utilize motorized multilane treadmills and single lane treadmill equipped with gas exchange chamber for indirect calorimetry computations. We utilize a variety of exercise profiles, e.g. VO2max exhaustive, stepwise incremental and etc. Oxygen kinetics and VO2max measurements are routinely done. Resistance training regimens are being currently developed for the use in rodents.
Unloading is represented by the hindlimb suspension unweighing technique originally developed by Morey-Holton. We custom build 24 suspension cages and successfully implemented this technique to simulate "microgravity" conditions to study the time-course of atrophy of hindlimb "anti-gravity" muscles. By the two weeks of suspension, animals lose up to 40% of soleus muscle and 10% of the Gastrocnemius muscle. We are currently studying a wide variety of whole-body adaptations to "microgravity" conditions imposed by hindlimb suspension.
Present Studies
Presently we are studying the effects of skeletal muscle atrophy during hindlimb suspension (HLS) and hypertrophy during endurance exercise training on respiratory metabolic performance. This study investigates whether impaired aerobic capacity previously observed in HLS rats is reversible by exercise training. The lab is also investigating the acute and chronic effects of exercise on whole body metabolic and physiological functions in genetically modified mice that promote "spontaneous" development of disease (e.g., cancer or cystic fibrosis) as well as transgenic mice in which the gene for PEPCK-C enzyme has been over-expressed in the skeletal muscle (PEPCK-Cmus). Data from some of these studies are being used to build a multi-scale computational model related to skeletal muscle metabolism in the context of the whole body. This model will help us to predict the integrated response of muscle fibers, whole skeletal muscle, and whole body during periods of loading and unloading.