title: Structural and Ultrastructural Characteristics of Bone-Tendon Junction of the Calcaneal Tendon of Adult and Elderly Wistar Rats.
abstract: Tendons are transition tissues that transfer the contractile forces generated by the muscles to the bones, allowing movement. The region where the tendon attaches to the bone is called bone-tendon junction or enthesis and may be classified as fibrous or fibrocartilaginous. This study aims to analyze the collagen fibers and the cells present in the bone-tendon junction using light microscopy and ultrastructural techniques as scanning electron microscopy and transmission electron microscopy. Forty male Wistar rats were used in the experiment, being 20 adult rats at 4 months-old and 20 elderly rats at 20 months-old. The hind limbs of the rats were removed, dissected and prepared to light microscopy, transmission electron microscopy and scanning electron microscopy. The aging process showed changes in the collagen fibrils, with a predominance of type III fibers in the elderly group, in addition to a decrease in the amount of the fibrocartilage cells, fewer and shorter cytoplasmic processes and a decreased synthetic capacity due to degradation of the organelles involved in synthesis.
authors.affiliation: Department of Anatomy, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil.|Department of Surgery, School of Veterinary Medicine and Animal Science, University of São Paulo, São Paulo, Brazil.
authors.forename: Diego Pulzatto
authors.initials: DP
authors.lastname: Cury
authors.affiliation: Department of Surgery and Anatomy, School of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto, Brazil.|CICO Research Centre, Dental School, Universidad de La Frontera, Temuco, Chile.
authors.forename: Fernando José
authors.initials: FJ
authors.lastname: Dias
authors.affiliation: Department of Surgery, School of Veterinary Medicine and Animal Science, University of São Paulo, São Paulo, Brazil.
authors.forename: Maria Angélica
authors.initials: MA
authors.lastname: Miglino
authors.affiliation: Department of Anatomy, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil.|Department of Surgery, School of Veterinary Medicine and Animal Science, University of São Paulo, São Paulo, Brazil.
authors.forename: Ii-sei
authors.initials: IS
authors.lastname: Watanabe
mesh_terms: D000125:Achilles Tendon / Q000648:ultrastructure*; D000375:Aging; D000818:Animals; D001842:Bone and Bones / Q000648:ultrastructure*; D024022:Fibrillar Collagens / Q000032:analysis*; D008297:Male; D017208:Rats, Wistar
chemical_list: D024022:Fibrillar Collagens