Age Effects On The Tensile And Stress Relaxation Properties Of Mouse Tail Tendons

摘要

Tendons are known to exhibit complex mechanical behavior when transferring forces from muscles to bone. This nonlinear mechanical response varies with age due to the presence of degenerative effects which is attributed to the structural changes and interactions observed in each hierarchical level of the dense connective tissue. In this study, mouse tail tendons were excised from the C57BL6 mice to evaluate the age effects on tensile and stress relaxation properties. Uniaxial tests were performed on two age groups: 1-month-old and 8-month-old. The extension rate effects on the ultimate tensile strength (UTS) and modulus were evaluated. The stress decay and relaxation rate were also analyzed. Polynomial function and power law were used to evaluate the modulus and the relaxation rate respectively. The extension rate effect on the UTS and modulus were significantly different for the younger group but the difference were not observed on the older group. Furthermore, the failure modes were observed to be complete for the younger group and non-uniform for the older groups when rupture sites were observed. The younger group demonstrated a faster relaxation as compared to the older group. These results suggested that the physiological changes which take place due to aging provide quantitative evidence of changes in the mechanical properties of tendons. Future work on other age groups are in progress.