title: Apoptosis in the supraspinatus tendon with stage II subacromial impingement.
abstract: The purpose of this study was to investigate the histopathology, including apoptosis, in the supraspinatus tendon with stage II subacromial impingement. Samples from the critical zone of the supraspinatus tendon were obtained from 5 patients with subacromial impingement syndrome and 10 autopsy cases without shoulder diseases as controls. Three-micrometer-thick sections were cut and stained with hematoxylin-eosin (H-E) for routine histologic examination. Apoptosis was detected by terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end labeling (TUNEL) method and single-stranded deoxyribonucleic acid (ssDNA) assay in which the frequency of the apoptotic cells was expressed by the apoptotic index. Control supraspinatus tendons showed normal morphology, whereas supraspinatus tendons from shoulders with impingement showed significant mucoid degeneration. Correspondingly, few apoptotic cells were observed in control tendons, whereas a large number of apoptotic cells were observed in the degenerative area of tendons from impingement shoulders. The apoptotic indices were significantly higher in the impingement shoulders (ssDNA, 18.84% +/- 1.75%; TUNEL, 24.92% +/- 2.79%) than in the control shoulders (ssDNA, 5.22% +/- 1.30%; TUNEL, 7.01% +/- 1.05%) (P = .04 for ssDNA and P = .017 for TUNEL). Mechanical impingement seems to cause tendon degeneration and apoptosis of the tendon cells in the supraspinatus tendon in stage II impingement.
authors.affiliation: Department of Orthopedic Surgery, Akita University School of Medicine, Akita, Japan.
authors.forename: Yilihamu
authors.initials: Y
authors.lastname: Tuoheti
authors.forename: Eiji
authors.initials: E
authors.lastname: Itoi
authors.forename: Rabindra L
authors.initials: RL
authors.lastname: Pradhan
authors.forename: Ikuko
authors.initials: I
authors.lastname: Wakabayashi
authors.forename: Shu
authors.initials: S
authors.lastname: Takahashi
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Minagawa
authors.forename: Moto
authors.initials: M
authors.lastname: Kobayashi
authors.forename: Kyoji
authors.initials: K
authors.lastname: Okada
authors.forename: Yoichi
authors.initials: Y
authors.lastname: Shimada
mesh_terms: D017209:Apoptosis / Q000502:physiology*; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D020287:In Situ Nick-End Labeling; D008297:Male; D017006:Rotator Cuff; D019534:Shoulder Impingement Syndrome / Q000473:pathology*; D013710:Tendons / Q000473:pathology*