Research Project Summaries

Undergraduate students Travis and Kate, doing research in the Department of Health and Nutrition Sciences at Idaho State University in 2009 with Dr. Cynthia Blanton (not shown) and Dr. Annette Gabaldón (left). We are dissecting rat hindlimb bones and skeletal muscles for the synbiotic diet studies.   

Undergraduate student Maureen Choman, doing summer research at CSU-Pueblo in 2011 as a visiting student from Notre Dame.  Maureen is capturing digital images of H&E stained rat soleus muscle slices to determine the effects of simulated weightlessness and dietary synbiotics on muscle total cross-sectional area (CSA) and fascicle area as indices of muscle strength.  Maureen is a pre-medical student who plans to pursue a combined M.D./Ph.D. program.


Rat soleus muscles were analyzed for CSA using the NIH Image J program to process digital images. 


Soleus muscle CSA from a loaded rat that was not hindlimb suspended.


Soleus muscle CSA from a rat that was hindlimb suspended for 14 days, showing significant atrophy.

Undergraduate students Maureen Choman (left) and Phylicia Sandoval (right), doing summer research at CSU-Pueblo in 2011.  They are preparing rat bone samples for ICP-MS analysis of bone major minerals and trace elements. The bones were ashed in a muffle furnace and are being digested in nitric acid solution.  Phylicia is a Biology major at CSU-Pueblo who plans to pursue a Physician’s Assistant degree program. 


Preparing ash samples for ICP-MS analysis.


Bones after ashing in a muffle furnace. 

Undergraduate student Maureen Choman, doing summer research at CSU-Pueblo in 2011.  She is preparing rat bones for volumetric density measurements using Archimedes’ Principle.  Because bone is a porous tissue that can trap air after dissection, the samples are degassed under vacuum in a saline solution to draw out air prior to volumetric density testing.


Rat femur bones being degassed in saline under vacuum to remove trapped air. 


Maureen setting up the degassing system.


Three-point bending tester for rat bone mechanical strength tests.   A three-point bending tester was designed and constructed by faculty and undergraduate students in the Engineering Department at CSU-Pueblo.  The tester evaluates bending strength of materials such as metal rods and animal bones.  A rat femur bone is supported by two points in an anterior-posterior plane, and a third point is driven by a motor onto the midshaft region of the bone at a constant rate of 0.2 millimeters per second until critical failure/fracture of the bone.  Load-displacement curves are generated for analysis of bone strength and stiffness.

Engineering undergraduate students Jon Berry (left) and William Berry (right) at CSU-Pueblo, testing a rat bone sample.

A rat femur bone is positioned in the anterior-posterior plane for three-point mechanical strength testing.  The anterior surface is facing up.

Three-point bending tester designed and constructed by faculty and undergraduate students in engineering at CSU-Pueblo.

Load-deformation curves for the femur bone in rats that were loaded, i.e. weight-bearing on all four limbs, and fed a control rat chow diet.


Bone testing team (left to right): Dr. Huseyin Sarper, William Berry, Dr. Jude Depalma, Yudhi, Dr. Annette Gabaldón, and Jon Berry. Special thanks to Paul Wallace (not shown) for the design and construction of the machine, and to all the other engineering students who helped. 

Video of three-point bending test of a rat bone.  The bone being tested is the femur in the anterior-posterior plane.  A high-speed video camera would slow this down to show the details of the fracture.  Once the force point is applied to the bone surface, the fracture occurs within a few milliseconds. Sensors detect force and deflection, enabling us to calculate maximum force at bone fracture and Young’s modulus of elasticity for bone stiffness. 


*Video link inserted here. MVI_4749 (3 pt bend femur).avi

Three-point bending test for one rat   femur bone showing bending up to the maximum force, at which time the bone fractures (Fmax is ~145 N in this test).

Rat bone micro-computed tomography (CT) scan.  The scan is of the rat tibia bone at the proximal end.  The trabecular bone is shaded green and cortical bone is shaded red.  Bone parameters analyzed included cortical wall density, thickness, and volume, and trabecular bone density, thickness, and lattice spacing.  Reference: Blanton, C. and A.M. Gabaldón (2012). Effect of dietary synbiotics on bone in mature male rats following recovery from hindlimb unloading. Int. J. Probiotics Prebiotics. in press.


Behavioral thermoregulation in senescent rats in response to acute cold exposure.  An illustration of the system that was designed and used for measurement of oxygen consumption, body core temperature, and behavioral thermoregulation of rats in a thermal gradient.  This was a longitudinal study performed on aging male Fischer 344 (F344) rats as they transitioned into senescence.  The transition to this end-of-life biological stage is characterized by spontaneous rapid body weight loss, cold intolerance, and altered circadian rhythms of body temperature.

Open respirometry system for measuring oxygen consumption rate in senescent F344 rats during acute cold exposure (Part 1) and in a thermal gradient (Part 2).  A radiotelemetry system (Minimitter) was used to remotely monitor body core temperature.  A video camera was used to capture the rat’s body position and location in the thermal gradient for behavioral analysis.



Thermal gradient pilot studies on a male F344 rat.  This is a very early design of the thermal gradient. The chamber is designed for behavioral monitoring but not for metabolic rate measurements.  The final design and construction of the chamber was done by a machinist in Pueblo, CO, and is shown above.  Students developed a protocol for behavioral monitoring of the rat using this early type thermal gradient.  This included scoring the activity level, body posture, and mapping temperature zones.

Please contact Dr. Gabaldón with any questions related to past or ongoing research activities. 
Selected Student Poster Presentations

Other Interests

Turkey treadmill training at Oregon State University in 2003, during postdoctoral research training in animal locomotion with Dr. Thomas Roberts, now at Brown University.  Working with student, Arianna.