title: Three-dimensional ultrastructural analysis of development at the supraspinatus insertion by using focused ion beam/scanning electron microscope tomography in rats.
abstract: To obtain a successful outcome after rotator cuff repair, the repaired tendon must be biologically anchored to the bone. However, the histological structure at the repaired tendon-bone interface differs from that of the site of normal tendon insertion. Therefore, analyzing postnatal development in detail will contribute to understanding the repaired tendon-bone interface after rotator cuff repair. In this study, we analyzed postnatal development at the tendon-bone insertion in terms of temporal changes in SOX9/SCX expression and three-dimensional (3D) ultrastructure with FIB/SEM tomography, a new scanning electron microscopic method. Sixteen postnatal Sprague-Dawley rats were used for the study. One-, two-, three-, and four-week-old rats were sacrificed and both right and left shoulders were removed; eight normal supraspinatus tendon insertions were isolated for each time point. At each time point, four specimens were evaluated with fluorescent immunostaining for SOX9/SCX expression, and the remaining four specimens were evaluated with FIB/SEM tomography. Even in postnatal development, SOX9(+) /SCX(+) expression was observed at the tendon insertion; expression gradually decreased with postnatal development at the normal tendon insertion. In 3D ultrastructure, the morphology of the cells and the number/orientation of the cell processes drastically changed by postnatal week 4. The pattern of SOX9/SCX expression and 3D ultrastructural changes obtained in this study contribute to an understanding of the complicated development of normal tendon-bone insertion. Therefore, this study helps elucidate the pathophysiology of tendon-bone insertion, especially in cases of rotator cuff tear and repair. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:969-976, 2016.
authors.affiliation: Division of Microscopic and Development Anatomy, Department of Anatomy, Kurume University School of Medicine, 67 Asahi-machi, Kurume City, Fukuoka, 830-0011, Japan.|Department of Orthopaedic Surgery, Kurume University School of Medicine, 67 Asahi-machi, Fukuoka, Kurume City, Fukuoka, 830-0011, Japan.
authors.forename: Tomonoshin
authors.initials: T
authors.lastname: Kanazawa
authors.affiliation: Department of Orthopaedic Surgery, Kurume University School of Medicine, 67 Asahi-machi, Fukuoka, Kurume City, Fukuoka, 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, 67 Asahi-machi, Kurume City, Fukuoka, 830-0011, Japan.
authors.forename: Keisuke
authors.initials: K
authors.lastname: Ohta
authors.affiliation: Department of Orthopaedic Surgery, Kurume University School of Medicine, 67 Asahi-machi, Fukuoka, Kurume City, Fukuoka, 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, 67 Asahi-machi, Kurume City, Fukuoka, 830-0011, Japan.
authors.forename: Kei-Ichiro
authors.initials: K
authors.lastname: Nakamura
mesh_terms: D000818:Animals; D051792:Basic Helix-Loop-Helix Proteins / Q000378:metabolism*; D055032:Electron Microscope Tomography; D021621:Imaging, Three-Dimensional; D008855:Microscopy, Electron, Scanning; D010012:Osteogenesis; D017207:Rats, Sprague-Dawley; D017006:Rotator Cuff / Q000000981:diagnostic imaging / Q000254:growth & development* / Q000378:metabolism / Q000648:ultrastructure*; D000070636:Rotator Cuff Injuries; D055758:SOX9 Transcription Factor / Q000378:metabolism*
chemical_list: D051792:Basic Helix-Loop-Helix Proteins; D055758:SOX9 Transcription Factor; C503819:Scx protein, rat
keywords: FIB/SEM tomography; rotator cuff; shoulder; tendon-to-bone healing