title: A method to test contractility of the supraspinatus muscle in mouse, rat, and rabbit.
abstract: The rotator cuff (RTC) muscles not only generate movement but also provide important shoulder joint stability. RTC tears, particularly in the supraspinatus muscle, are a common clinical problem. Despite some biological healing after RTC repair, persistent problems include poor functional outcomes with high retear rates after surgical repair. Animal models allow further exploration of the sequela of RTC injury such as fibrosis, inflammation, and fatty infiltration, but there are few options regarding contractility for mouse, rat, and rabbit. Histological findings can provide a "direct measure" of damage, but the most comprehensive measure of the overall health of the muscle is contractile force. However, information regarding normal supraspinatus size and contractile function is scarce. Animal models provide the means to compare muscle histology, imaging, and contractility within individual muscles in various models of injury and disease, but to date, most testing of animal contractile force has been limited primarily to hindlimb muscles. Here, we describe an in vivo method to assess contractility of the supraspinatus muscle and describe differences in methods and representative outcomes for mouse, rat, and rabbit.
authors.affiliation: Department of Orthopaedics, University of Maryland School of Medicine, Baltimore, Maryland; and Department of Kinesiology, University of Maryland School of Public Health, College Park, Maryland.
authors.forename: Ana P
authors.initials: AP
authors.lastname: Valencia
authors.affiliation: Department of Orthopaedics, University of Maryland School of Medicine, Baltimore, Maryland; and.
authors.forename: Shama R
authors.initials: SR
authors.lastname: Iyer
authors.affiliation: Department of Orthopaedics, University of Maryland School of Medicine, Baltimore, Maryland; and.
authors.forename: Stephen J P
authors.initials: SJP
authors.lastname: Pratt
authors.affiliation: Department of Orthopaedics, University of Maryland School of Medicine, Baltimore, Maryland; and.
authors.forename: Mohit N
authors.initials: MN
authors.lastname: Gilotra
authors.affiliation: Department of Orthopaedics, University of Maryland School of Medicine, Baltimore, Maryland; and rlovering@som.umaryland.edu.
authors.forename: Richard M
authors.initials: RM
authors.lastname: Lovering
mesh_terms: D000818:Animals; D004195:Disease Models, Animal; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D009119:Muscle Contraction / Q000502:physiology*; D009133:Muscular Atrophy / Q000503:physiopathology; D009135:Muscular Diseases / Q000503:physiopathology; D011817:Rabbits; D051381:Rats; D017207:Rats, Sprague-Dawley; D017006:Rotator Cuff / Q000502:physiology*
keywords: muscle force; muscle function; rotator cuff