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A novel animal model for external anal sphincter insufficiency

Brügger, Lukas ; Inglin, Roman ; Candinas, Daniel ; Sulser, Tullio ; Eberli, Daniel

In: International Journal of Colorectal Disease, 2014, vol. 29, no. 11, p. 1385-1392

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    Title
    • A novel animal model for external anal sphincter insufficiency
    Author
    • Brügger, Lukas. Laboratory for Urologic Tissue Engineering and Stem Cell Therapy, Department of Urology, University Hospital Zürich, Frauenklinikstrasse 10, 8091, Zürich, Switzerland
    • Inglin, Roman. Laboratory for Urologic Tissue Engineering and Stem Cell Therapy, Department of Urology, University Hospital Zürich, Frauenklinikstrasse 10, 8091, Zürich, Switzerland
    • Candinas, Daniel. Department of Visceral Surgery and Medicine, Bern University Hospital, University of Bern, Freiburgstrasse 4, 3010, Bern, Switzerland
    • Sulser, Tullio. Laboratory for Urologic Tissue Engineering and Stem Cell Therapy, Department of Urology, University Hospital Zürich, Frauenklinikstrasse 10, 8091, Zürich, Switzerland
    • Eberli, Daniel. Laboratory for Urologic Tissue Engineering and Stem Cell Therapy, Department of Urology, University Hospital Zürich, Frauenklinikstrasse 10, 8091, Zürich, Switzerland
    Document Type
    • Postprint
    Language
    • English
    Published in
    • International Journal of Colorectal Disease, 2014, vol. 29, no. 11, p. 1385-1392. Springer Berlin Heidelberg
    Other Version
    OAI-PMH Identifier
    • oai:doc.rero.ch:326050
    Summary
    Purpose: Reliable animal models are essential to evaluate future therapeutic options like cell-based therapies for external anal sphincter insufficiency. The goal of our study was to describe the most reliable model for external sphincter muscle insufficiency by comparing three different methods to create sphincter muscle damage. Methods: In an experimental animal study, female Lewis rats (200-250g) were randomly assigned to three treatment groups (n = 5, each group). The external sphincter muscle was weakened in the left dorsal quadrant by microsurgical excision, cryosurgery, or electrocoagulation by diathermy. Functional evaluation included in vivo measurements of resting pressure, spontaneous muscle contraction, and contraction in response to electrical stimulation of the afferent nerve at baseline and at 2, 4, and 6weeks after sphincter injury. Masson's trichrome staining and immunofluorescence for skeletal muscle markers was performed for morphological analysis. Results: Peak contraction after electrical stimulation was significantly decreased after sphincter injury in all groups. Contraction forces recovered partially after cryosurgery and electrocoagulation but not after microsurgical excision. Morphological analysis revealed an incomplete destruction of the external sphincter muscle in the cryosurgery and electrocoagulation groups compared to the microsurgery group. Conclusions: For the first time, three different models of external sphincter muscle insufficiency were directly compared. The animal model using microsurgical sphincter destruction offers the highest level of consistency regarding tissue damage and sphincter insufficiency, and therefore represents the most reliable model to evaluate future therapeutic options. In addition, this study represents a novel model to specifically test the external sphincter muscle function.