title: Non-mineralized fibrocartilage shows the lowest elastic modulus in the rabbit supraspinatus tendon insertion: measurement with scanning acoustic microscopy.
abstract: The acoustic properties of rabbit supraspinatus tendon insertions were measured by scanning acoustic microscopy. After cutting parallel to the supraspinatus tendon fibers, specimens were fixed with 10% neutralized formalin, embedded in paraffin, and sectioned. Both the sound speed and the attenuation constant were measured at the insertion site. The 2-dimensional distribution of the sound speed and that of the attenuation constant were displayed with color-coded scales. The acoustic properties reflected both the histologic architecture and the collagen type. In the tendon proper and the non-mineralized fibrocartilage, the sound speed and attenuation constant gradually decreased as the predominant collagen type changed from I to II. In the mineralized fibrocartilage, they increased markedly with the mineralization of the fibrocartilaginous tissue. These results indicate that the non-mineralized fibrocartilage shows the lowest elastic modulus among 4 zones at the insertion site, which could be interpreted as an adaptation to various types of biomechanical stress.
authors.affiliation: Department of the Orthopaedic Surgery, Tohoku University School of Medicine, Sendai, Japan. staka@mail.tains.tohoku.ac.jp <staka@mail.tains.tohoku.ac.jp>
authors.forename: Hirotaka
authors.initials: H
authors.lastname: Sano
authors.forename: Yoshifumi
authors.initials: Y
authors.lastname: Saijo
authors.forename: Shoichi
authors.initials: S
authors.lastname: Kokubun
mesh_terms: D000222:Adaptation, Physiological / Q000502:physiology; D000818:Animals; D001696:Biomechanical Phenomena; D024042:Collagen Type I / Q000032:analysis; D024043:Collagen Type II / Q000032:analysis; D004548:Elasticity; D051445:Fibrocartilage / Q000737:chemistry / Q000000981:diagnostic imaging* / Q000502:physiology; D008297:Male; D033401:Microscopy, Acoustic; D018482:Muscle, Skeletal / Q000737:chemistry / Q000000981:diagnostic imaging / Q000502:physiology; D011817:Rabbits; D013314:Stress, Mechanical; D013710:Tendons / Q000737:chemistry / Q000000981:diagnostic imaging* / Q000502:physiology
chemical_list: D024042:Collagen Type I; D024043:Collagen Type II