Intrinsic healing capacity and tearing process of torn supraspinatus tendons: in situ hybridization study of alpha 1 (I) procollagen mRNA.
To determine the healing potential and healing process of torn supraspinatus tendons, in situ hybridization was used to localize cells containing alpha 1 type-I procollagen mRNA. Biopsy specimens of torn supraspinatus tendons from 19 patients with complete-thickness tears and 13 patients with incomplete-thickness tears were obtained during surgery. Four macroscopically normal supraspinatus tendons were obtained to serve as normal controls. Specimens were fixed in 10% buffered formalin and embedded in paraffin. A 22-mer oligonucleotide probe was labeled with digoxigenin and used as an in situ marker. The labeled cells were mainly composed of tenocytes and undifferentiated mesenchymal cells. In complete-thickness-tears, the labeled cells at the proximal tendon-stumps in the specimens that were obtained less than 4 months after trauma were significantly more abundant than in the specimens obtained 4 months or more after trauma. However, the number of labeled cells was maintained at the torn portion even in long-standing incomplete-thickness tears. The labeled cells at the margins of concomitant intratendinous extensions of the tears were detected even in the long-standing tears. The intratendinous extensions exhibited more labeled cells than the bursal-side or joint-side layers of the tendon substance in the incomplete-thickness tears (p < 0.05). The torn supraspinatus tendon may possess an intrinsic healing capability in the intermediate and late phases of tendon healing. Incomplete-thickness tears and concomitant intratendinous extensions can continue to rupture after the initial injury.
Hamada
K
K
Department of Orthopaedics, Tokai University School of Medicine, Kanagawa, Japan. kazuhama@is.icc.u-tokai.ac.jp
Tomonaga
A
A
Gotoh
M
M
Yamakawa
H
H
Fukuda
H
H
D000328:Adult; D000368:Aged; D016375:Antisense Elements (Genetics); D015152:Blotting, Northern; D006801:Humans; D017403:In Situ Hybridization; D008875:Middle Aged; D011347:Procollagen / Q000235:genetics*; D012333:RNA, Messenger / Q000032:analysis; D012260:Ribonucleases; D013708:Tendon Injuries / Q000473:pathology / Q000503:physiopathology*; D013710:Tendons / Q000737:chemistry / Q000473:pathology / Q000502:physiology; D014945:Wound Healing / Q000502:physiology*
D016375:Antisense Elements (Genetics); D011347:Procollagen; D012333:RNA, Messenger; D012260:Ribonucleases