DOS Kongressen 2014 ·
215
Collagen types and distribution at the human
myotendinous junction (MTJ)
Jens Rithamer Jakobsen, Abigail Mackey, Andreas Knudsen, Manuel Koch,
Michael Kjaer, Michael Rindom Krogsgaard
Department of sportstraumatology M51, , Bispebjerg Hospital, University
of Copenhagen, Denmark.; Institute of Sports Medicine Copenhagen,
Department of Orthopaedic Surgery M, and Department of Biom, Bispebjerg
University Hospital and University of Copenhagen; Institute for Dental
Research and Oral Musculoskeletal Biology, and Center for Biochemistry,
Medical Faculty, University of Cologne, Cologne, Germany
Background:
The MTJ is the interface between the muscle and tendon, through
which force produced in the muscle is transmitted. Excessive loading of muscles
can result in strain injuries, which often occur at the MTJ. However, very little is
known about the composition of the human MTJ. In animals, collagen type XXII
seems to be located exclusively in the MTJ, and has been shown to contribute to
the stabilization of MTJ and strengthening of skeletal muscle attachments dur-
ing contraction. Similarly, a lack of Collagen XXII results in a higher susceptibility
to ruptures of the MTJ.
Purpose / Aim of Study:
The aim of this study is to investigate the distribution
of collagen type XXII in human MTJ and the localisation of other collagen types
(I, III, VI, XII, XIV) in relation to collagen XXII.
Materials and Methods:
Samples of MTJ were collected from the hamstring
muscles of 15 patients during ACL-reconstruction and frozen in liquid nitrogen,
cut on a cryostat and stained with antibodies against collagen I, III, IV, VI, XII, XIV
and XXII. The sections were analysed immunohistochemically with fluorescent
wide-field and confocal microscopes and the amounts of stained protein were
estimated visually on a score from 0 to 2, where 2 is highest.
Findings / Results:
Collagen XXII was located only at the MTJ, but not in all
regions. It was detected between the dystrophin-labelled myofibre membrane
and the endomysium, which was rich in collagen types III and VI. Collagen types
XII and XIV were also observed to be closely associated with XXII.
Conclusions:
The human MTJ has a very complex composition of different col-
lagen types. The possible roles of these collagens in force transmission are dis-
cussed. Collagen type XXII was the only type to be solely located at the MTJ,
and is therefore a valuable marker for human MTJ even though it is not found in
all regions.
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