MABITEM: A Murine Aorta Biaxial Testing Machine
Biaxial testing of blood vessels is the preferred method for biomechanical testing because of its ability to provide a measure of the anisotropy of these tissues. Small-caliber vessels are usually subjected to tubular biaxial testing due to the impracticality of mounting such delicate planar samples in planar biaxial tensile testers, and because undesired stresses may be introduced by the flattening process. In addition, if the end goal of the testing is constitutive modeling and identification of relevant mechanical properties of the blood vessel, tubular biaxial testing may be the most practical method. An appropriate biomechanical testing system should enable the user to carefully control the geometry, loading, preloading, and testing of the specimens, while simultaneously maintain the pH, temperature, and humidity representative of in vivo conditions. The aim of this research is to design and build a computer-controlled small-caliber vessel biomechanical testing machine and demonstrate its capabilities for assessing the mechanics of murine abdominal aortas. The system, named MABITEM, is envisioned to be readily adaptable for mechanical testing of other blood vessels, hence providing benefit to general vascular biomechanics research. Abdominal aortas from mice treated with Dotarem®, a gadolinium-based magnetic resonance imaging (MRI) agent, were mechanically tested using MABITEM and compared to control groups to show the capabilities of the system and the effects of the treatment. The results obtained suggest that Dotarem® does not affect the biomechanics of mice abdominal aortas and demonstrate the functionality of MABITEM for the quantification of biomechanics of small-caliber vessels.