An AFM study of the nanostructural response of New Zealand white rabbit Achilles tendons to cyclic loading

• Published in: Microscopy research and technique Vol. 85; no. 2; pp. 728 - 737
• Main Authors: Al Makhzoomi, Anas K., Kirk, Thomas B., Allison, Garry T.
• Format: Journal Article
• Language: English
• Published: Hoboken, USA John Wiley & Sons, Inc 01.02.2022; Wiley Subscription Services, Inc
• Subjects: Achilles Tendon; Animals; Atomic force microscopy; Biomechanical Phenomena; concurrent nanostructural and mechanical assessment; Cyclic loads; Cytoskeleton; Damage assessment; D‐periodicity; Elongation; Fatigue failure; Materials fatigue; Mechanical properties; Microscopy, Atomic Force; Nanostructures; Periodicity; Rabbits; Structure-function relationships; tendon structure–function relationships; Tendons; New Zealand; D-periodicity; atomic force microscopy; concurrent nanostructural and mechanical assessment; tendon structure-function relationships
• ISSN: 1059-910X; 1097-0029
• DOI: 10.1002/jemt.23944

The nanostructural response of New Zealand white rabbit Achilles tendons to a fatigue damage model was assessed quantitatively and qualitatively using the endpoint of dose assessments of each tendon from our previous study. The change in mechanical properties was assessed concurrently with nanostructural change in the same non‐viable intact tendon. Atomic force microscopy was used to study the elongation of D‐periodicities, and the changes were compared both within the same fibril bundle and between fibril bundles. D‐periodicities increased due to both increased strain and increasing numbers of fatigue cycles. Although no significant difference in D‐periodicity lengthening was found between fibril bundles, the lengthening of D‐periodicity correlated strongly with the overall tendon mechanical changes. The accurate quantification of fibril elongation in response to macroscopic applied strain assisted in assessing the complex structure–function relationship in Achilles tendons. The form and function of tendons are highly correlated at nanoscopic scale. Mechanical load is uniformly distributed and homogenous among the WFB and BFB networks. Tendon damage accumulation is cycle‐dependent mechanism.