title: Histomorphometric and ultrastructural analysis of the tendon-bone interface after rotator cuff repair in a rat model.
abstract: Successful rotator cuff repair requires biological anchoring of the repaired tendon to the bone. However, the histological structure of the repaired tendon-bone interface differs from that of a normal tendon insertion. We analysed differences between the normal tendon insertion and the repaired tendon-bone interface after surgery in the mechanical properties, histomorphometric analysis, and 3-dimensional ultrastructure of the cells using a rat rotator cuff repair model. Twenty-four adult Sprague-Dawley (SD) rats underwent complete cuff tear and subsequent repair of the supraspinatus tendon. The repaired tendon-bone interface was evaluated at 4, 8, and 12 weeks after surgery. At each time point, shoulders underwent micro-computed tomography scanning and biomechanical testing (N = 6), conventional histology and histomorphometric analysis (N = 6), and ultrastructural analysis with focused ion beam/scanning electron microscope (FIB/SEM) tomography (N = 4). We demonstrated that the cellular distribution between the repaired tendon and bone at 12 weeks after surgery bore similarities to the normal tendon insertion. However, the ultrastructure of the cells at any time point had a different morphology than those of the normal tendon insertion. These morphological differences affect the healing process, partly contributing to re-tearing at the repair site. These results may facilitate future studies of the regeneration of a normal tendon insertion.
authors.affiliation: Division of Microscopic and Development Anatomy, Department of Anatomy, Kurume University School of Medicine, Kurume, 830-0011, Japan.|Department of Orthopaedic surgery, Kurume University School of Medicine, Kurume, 830-0011, Japan.
authors.forename: Tomonoshin
authors.initials: T
authors.lastname: Kanazawa
authors.affiliation: Department of Orthopaedic surgery, Kurume University School of Medicine, Kurume, 830-0011, Japan.
authors.forename: Masafumi
authors.initials: M
authors.lastname: Gotoh
authors.affiliation: Division of Microscopic and Development Anatomy, Department of Anatomy, Kurume University School of Medicine, Kurume, 830-0011, Japan.
authors.forename: Keisuke
authors.initials: K
authors.lastname: Ohta
authors.affiliation: Department of Orthopaedic surgery, Kurume University School of Medicine, Kurume, 830-0011, Japan.
authors.forename: Hirokazu
authors.initials: H
authors.lastname: Honda
authors.affiliation: Department of Orthopaedic surgery, Kurume University School of Medicine, Kurume, 830-0011, Japan.
authors.forename: Hiroki
authors.initials: H
authors.lastname: Ohzono
authors.affiliation: Department of Orthopaedic surgery, Kurume University School of Medicine, Kurume, 830-0011, Japan.
authors.forename: Hisao
authors.initials: H
authors.lastname: Shimokobe
authors.affiliation: Department of Orthopaedic surgery, Kurume University School of Medicine, Kurume, 830-0011, Japan.
authors.forename: Naoto
authors.initials: N
authors.lastname: Shiba
authors.affiliation: Division of Microscopic and Development Anatomy, Department of Anatomy, Kurume University School of Medicine, Kurume, 830-0011, Japan.
authors.forename: Kei-Ichiro
authors.initials: K
authors.lastname: Nakamura
mesh_terms: D000818:Animals; D004195:Disease Models, Animal; D051381:Rats; D017207:Rats, Sprague-Dawley; D017006:Rotator Cuff / Q000503:physiopathology / Q000601:surgery / Q000648:ultrastructure; D000070636:Rotator Cuff Injuries / Q000473:pathology / Q000503:physiopathology / Q000601:surgery