Neer Award 2016: reduced muscle degeneration and decreased fatty infiltration after rotator cuff tear in a poly(ADP-ribose) polymerase 1 (PARP-1) knock-out mouse model

Michael B. Kuenzler, Katja Nuss, Agnieszka Karol, Michael O. Schär, Michael Hottiger, Sumit Raniga, David Kenkel, Brigitte von Rechenberg, Matthias A. Zumstein*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

16 Citations (Scopus)


Background Disturbed muscular architecture, atrophy, and fatty infiltration remain irreversible in chronic rotator cuff tears even after repair. Poly (adenosine 5′-diphosphate-ribose) polymerase 1 (PARP-1) is a key regulator of inflammation, apoptosis, muscle atrophy, muscle regeneration, and adipocyte development. We hypothesized that the absence of PARP-1 would lead to a reduction in damage to the muscle subsequent to combined tenotomy and neurectomy in a PARP-1 knockout (KO) mouse model. Methods PARP-1 KO and wild-type C57BL/6 (WT group) mice were analyzed at 1, 6, and 12 weeks (total n = 84). In all mice, the supraspinatus and infraspinatus muscles of the left shoulder were detached and denervated. Macroscopic analysis, magnetic resonance imaging, gene expression analysis, immunohistochemistry, and histology were used to assess the differences in PARP-1 KO and WT mice. Results The muscles in the PARP-1 KO group had significantly less retraction, atrophy, and fatty infiltration after 12 weeks than in the WT group. Gene expression of inflammatory, apoptotic, adipogenic, and muscular atrophy genes was significantly decreased in PARP-1 KO mice in the first 6 weeks. Discussion Absence of PARP-1 leads to a reduction in muscular architectural damage, early inflammation, apoptosis, atrophy, and fatty infiltration after combined tenotomy and neurectomy of the rotator cuff muscle. Although the macroscopic reaction to injury is similar in the first 6 weeks, the ability of the muscles to regenerate was much greater in the PARP-1 KO group, leading to a near-normalization of the muscle after 12 weeks.

Original languageEnglish
Pages (from-to)733-744
Number of pages12
JournalJournal of Shoulder and Elbow Surgery
Issue number5
Publication statusPublished - May 1 2017
Externally publishedYes


  • ARTD1
  • fatty infiltration
  • inflammation
  • knock out mouse model
  • muscle atrophy
  • PARP-1
  • Rotator cuff tear
  • supraspinatus muscle

ASJC Scopus subject areas

  • Surgery
  • Orthopedics and Sports Medicine

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