The tendon injury response is influenced by decorin and biglycan.
Defining the constituent regulatory molecules in tendon is critical to understanding the process of tendon repair and instructive to the development of novel treatment modalities. The purpose of this study is to define the structural, expressional, and mechanical changes in the tendon injury response, and elucidate the roles of two class I small leucine-rich proteoglycans (SLRPs). We utilized biglycan-null, decorin-null and wild type mice with an established patellar tendon injury model. Mechanical testing demonstrated functional changes associated with injury and the incomplete recapitulation of mechanical properties after 6 weeks. In addition, SLRP deficiency influenced the mechanical properties with a marked lack of improvement between 3 and 6 weeks in decorin-null tendons. Morphological analyses of the injury response and role of SLRPs demonstrated alterations in cell density and shape as well as collagen alignment and fibril structure resulting from injury. SLRP gene expression was studied using RT-qPCR with alterations in expression associated with the injured tendons. Our results show that in the absence of biglycan initial healing may be impaired while in the absence of decorin later healing is clearly diminished. This suggests that biglycan and decorin may have sequential roles in the tendon response to injury.
The McKay Orthopaedic Research Laboratory, University of Pennsylvania, 424 Stemmler Hall, 3450 Hamilton Walk, Philadelphia, PA, 19104, USA.
Andrew A
AA
Dunkman
Mark R
MR
Buckley
Michael J
MJ
Mienaltowski
Sheila M
SM
Adams
Stephen J
SJ
Thomas
Lauren
L
Satchell
Akash
A
Kumar
Lydia
L
Pathmanathan
David P
DP
Beason
Renato V
RV
Iozzo
David E
DE
Birk
Louis J
LJ
Soslowsky
D000818:Animals; D058578:Biglycan / Q000235:genetics / Q000378:metabolism*; D003094:Collagen / Q000096:biosynthesis / Q000235:genetics; D058575:Decorin / Q000235:genetics / Q000378:metabolism*; D004195:Disease Models, Animal; D005260:Female; D005786:Gene Expression Regulation; D051379:Mice; D018345:Mice, Knockout; D017847:Patellar Ligament / Q000293:injuries* / Q000378:metabolism* / Q000473:pathology; D013708:Tendon Injuries / Q000235:genetics / Q000378:metabolism* / Q000473:pathology
C546885:Bgn protein, mouse; D058578:Biglycan; C546879:Dcn protein, mouse; D058575:Decorin; D003094:Collagen