The Roles of Elastic Fibres and Glycosaminoglycans in the Radial Tensile Mechanics of the Human Lumbar Anulus Fibrosus

The anulus fibrosus of the human lumbar disc has a complex, hierarchical structure comprised of collagen, proteoglycan and elastic fibres [1,2]. Individually and through interactions, these constituents govern the complex, anisotropic mechanical reponse of the anulus; the exact nature of their contributions, however, remains unclear [3]. In the radial direction, mechanical behaviour is heterogeneous, varies with degenerative condition, and is thought to be governed largely by the matrix at lamellar interfaces [4,5]. The objectives of this study were to quantify the contributions made by both elastic fibres and glycosaminoglycans to the radial tensile reponse of the human lumbar anulus, using a combination of targeted enzymatic degradation and biomechanical testing.