title: Quantification of sarcomere length distribution in whole muscle frozen sections.
abstract: Laser diffraction (LD) is a valuable tool for measuring sarcomere length (Ls), a major determinant of muscle function. However, this method relies on few measurements per sample that are often extrapolated to whole muscle properties. Currently it is not possible to measure Ls throughout an entire muscle and determine how Ls varies at this scale. To address this issue, we developed an actuated LD scanner for sampling large numbers of sarcomeres in thick whole muscle longitudinal sections. Sections of high optical quality and fixation were produced from tibialis anterior and extensor digitorum longus muscles of Sprague-Dawley rats (N=6). Scans produced two-dimensional Ls maps, capturing >85% of the muscle area per section. Individual Ls measures generated by automatic LD and bright-field microscopy showed excellent agreement over a large Ls range (ICC>0.93). Two-dimensional maps also revealed prominent regional Ls variations across muscles.
authors.affiliation: Department of Bioengineering, University of California San Diego, La Jolla, CA 92093, USA Department of Orthopaedic Surgery, University of California San Diego, La Jolla, CA 92093, USA.
authors.forename: Shawn M
authors.initials: SM
authors.lastname: O'Connor
authors.affiliation: Department of Bioengineering, University of California San Diego, La Jolla, CA 92093, USA.
authors.forename: Elton J
authors.initials: EJ
authors.lastname: Cheng
authors.affiliation: Department of Bioengineering, University of California San Diego, La Jolla, CA 92093, USA Research Service, Veteran's Administration San Diego Healthcare System, San Diego, CA 92161, USA.
authors.forename: Kevin W
authors.initials: KW
authors.lastname: Young
authors.affiliation: Department of Bioengineering, University of California San Diego, La Jolla, CA 92093, USA Department of Orthopaedic Surgery, University of California San Diego, La Jolla, CA 92093, USA Research Service, Veteran's Administration San Diego Healthcare System, San Diego, CA 92161, USA Department of Radiology, University of California San Diego, La Jolla, CA 92093, USA.
authors.forename: Samuel R
authors.initials: SR
authors.lastname: Ward
authors.affiliation: Department of Bioengineering, University of California San Diego, La Jolla, CA 92093, USA Department of Orthopaedic Surgery, University of California San Diego, La Jolla, CA 92093, USA Research Service, Veteran's Administration San Diego Healthcare System, San Diego, CA 92161, USA Rehabilitation Institute of Chicago, Chicago, IL 60611, USA rlieber@ric.org.
authors.forename: Richard L
authors.initials: RL
authors.lastname: Lieber
mesh_terms: D000818:Animals; D005629:Frozen Sections; D007834:Lasers; D008297:Male; D018482:Muscle, Skeletal / Q000502:physiology*; D017207:Rats, Sprague-Dawley; D012146:Rest / Q000502:physiology; D012518:Sarcomeres / Q000502:physiology*
keywords: Laser diffraction; Muscle architecture; Sarcomere length