title: Evidence of a discrete axial structure in unimodal collagen fibrils.
abstract: The collagen fibrils of cornea, blood vessel walls, skin, gut, interstitial tissues, the sheath of tendons and nerves, and other connective tissues are known to be made of helically wound subfibrils winding at a constant angle to the fibril axis. A critical aspect of this model is that it requires the axial microfibrils to warp in an implausible way. This architecture lends itself quite naturally to an epitaxial layout where collagen microfibrils envelop a central core of a different nature. Here we demonstrate an axial domain in collagen fibrils from rabbit nerve sheath and tendon sheath by means of transmission electron microscopy after a histochemical reaction designed to evidence all polysaccharides and by tapping-mode atomic force microscopy. This axial domain was consistently found in fibrils with helical microfibrils but was not observed in tendon, whose microfibrils run longitudinal and parallel.
authors: Department of Human Morphology, Insubria University, Varese, Italy. mario.raspanti@uninsubria.it
authors: Mario
authors: M
authors: Raspanti
authors: Marcella
authors: M
authors: Reguzzoni
authors: Marina
authors: M
authors: Protasoni
authors: Désirée
authors: D
authors: Martini
mesh_terms: D000818:Animals; D002490:Central Nervous System / Q000737:chemistry*; D003094:Collagen / Q000737:chemistry* / Q000648:ultrastructure*; D003238:Connective Tissue; D005109:Extracellular Matrix; D020894:Microfibrils; D018625:Microscopy, Atomic Force / Q000379:methods; D008854:Microscopy, Electron; D011817:Rabbits; D013710:Tendons / Q000737:chemistry*
chemical_list: D003094:Collagen