The stress-strain behavior of rat pulmonary arteries was studied using a bubble inflation technique. To obtain mechanical properties, an analytical method to evaluate the bubble test results was developed. A flat disk of rat pulmonary artery was constrained at the periphery, inflated, and the geometry of the resulting bubble of material recorded from six different angles. Results of tests of pulmonary arteries from untreated Long-Evans rats are presented from three sections of the pulmonary artery: the trunk, and the right and left main extrapulmonary arteries. Analyses were conducted looking for behavioral differences between the flow (longitudinal) and the circumferential directions, between the right and the left main arteries, and between each of the mains and the trunk, There was no significant difference in mechanical properties between the circumferential and longitudinal orientations for any of the sections of the artery tested. The slope of the stress-strain curves at the end of the test, an indication of strain stiffening, was smaller for the trunk than for those of the left and right main extrapulmonary artery. The difference in slope was significant (P < 0.05) for the circumferential orientations, and for the longitudinal direction between the left main and trunk. These data provide the baseline stress-strain behavior of the pulmonary artery from normotensive rats.
Citation: Journal of Biomechanics
Pub Type: Journals
bubble test, mechanical properties of pulmonary arteries, pressure, pulmonary hypertension, strain, stress, stretch