APPLICATION OF CONFOCAL AND SECOND HARMONIC GENERATION MICROSCOPY TO STUDY THE 3D NETWORK OF ELASTIC FIBRES, COLLAGEN FIBRILS AND CELLS IN ACHILLES TENDONS

A tendon is a fibrous connective tissue that acts to transmit tensile forces between muscles and bones. It mainly consists of soluble substance, collagen and small volume of elastic fibres, which are produced by tenoblasts and tenocytes. The Achilles tendon is the thickest tendon in the human body that subjects to some of the highest tensile force, thus disorders and ruptures commonly happen. As the insoluble fibrous components in Achilles tendons, the collagen fibrils and elastic fibres have unique spatial structure that plays important functional roles. Despite this, the understanding of relationship between them is still limited due to the lack of imaging evidence. Using confocal and second harmonic generation microscopy, this study aims to comprehensively investigate the spatial relationship of collagen, elastic fibres and tenocytes in hydrated tendons.Longitudinal sections of 50 µm thick and transverse sections of 20 µm thick were cryo-sectioned respectively from the mid-portion of ten rabbit Achille...