Experimental estimation and comparison of viscoelastic characteristics of rat aorta in vitro

A. Georgiev, M. Kaneva, L. Shikova, M. Antonova

Abstract: The aim of the present work was to experimentally estimate and compare natural frequency, modulus of elasticity, and coefficient of viscosity of strip preparations of rat aorta. Materials and methods: The experimental setting included an improved apparatus, applying the forced oscillations method. Ten healthy Wistar rats, aged 4 (n = 7) and 14 months (n = 3), were sacrificed and the excised aortas were spirally cut into strip preparations. Forced oscillations were recorded for 4 suspended concentrated masses, equivalent to intraluminal pressure in the range 80-160 mmHg. Resonance curves were obtained and thereafter the natural frequency, 3dB width and octave length. Distension was measured at each equivalent pressure. Results: Natural frequency was estimated at 6.02-7.27 Hz (mature) versus 6.73-8.01 Hz (aged). Modulus of elasticity was higher for the aged aortas at 0.18-0.56 MPa versus 0.16-0.49 MPa for the mature. There was no statistically significant difference between the two age groups in terms of coefficient of viscosity. It was estimated at 0.008-0.023 N.s/m (mature) and 0.011-0.021 N.s/m (aged). Conclusion: The aged rat aorta is more threatened by high resonance oscillations than the mature aorta. The aged artery is less distensible than the mature one.

Series on Biomechanics, Vol.36 No.1 (2022), 86-97
DOI: 10.7546/SB.12.2022

Keywords: aorta; rat; viscoelasticity

Date published: 2022-04-12