Contributions of Collagen Fibers in the Mechanics of the Human Abdominal Aorta

The primary structural element responsible for sustaining mechanical loads in connective tissues, including bone, skin, and cartilage, is constituted by collagen fibers. The complex hierarchical structure and structural organisation of collagen, spanning from the molecular to the fiber level, significantly contribute to the mechanical properties exhibited by collagen-based tissues within a physiological setting. The primary objective of this study is to assess the structural changes occurring in the abdominal aorta (AA) under uniaxial load conditions. The application of Fourier transform Raman spectroscopy was utilised to assess the influence of collagen on the mechanical properties of the aorta. The Raman spectroscopy analysis of the aorta wall spectrum reveals increased intensities within the vibration bands of aromatic amino acids at 1616, 1604, 1207, and 757 cm−1. When exposed to mechanical stress, there is a decrease in the wavenumber of the C–C band, namely at 936 cm−1. This finding offers scientific backing for the theory that a decrease in the intensity of the Amide I peak is indicative of the alignment of collagen fibers in a parallel orientation relative to the direction of stretching.