3D analysis of aortic tissue deformation at micrometer scale during of intraluminal pressurization

Abstract

The aorta is stretched in the circumferential direction due to blood pressure. Although smooth muscle cells (SMCs) in the aorta have been thought to also undergo uniaxial circumferential stretch, it is debatable as they reside in a mechanically heterogeneous material composed of stiff elastin and collagens and compliant SMCs. We therefore investigated 3D deformation of a pressurized aortic tissue at a micrometer scale. Strain markers were made on elastic laminas of mouse thoracic aortas with a two-photon microscope. A local 3D strain tensor or aortic walls during pressurization was calculated. The result showed that physiological pressurization yielded some circumferential normal strain and zero normal longitudinal strain. Under the same pressurization, the radial-circumferential shear stain occurred. These results indicate that mechanical environment around SMCs in vivo is more complicated than expected.