title: Relaxin Receptor RXFP1 and RXFP2 Expression in Ligament, Tendon, and Shoulder Joint Capsule of Rats.
abstract: Numerous musculoskeletal disorders are caused by thickened ligament, tendon stiffness, or fibrosis of joint capsule. Relaxin, a peptide hormone, can exert collagenolytic effect on ligamentous and fibrotic tissues. We hypothesized that local injection of relaxin could be used to treat entrapment neuropathy and adhesive capsulitis. Because hormonal effect depends on the receptor of the hormone on the target cell, it is important to confirm the presence of such hormonal receptor at the target tissue before the hormone therapy is initiated. The aim of this study was to determine whether there were relaxin receptors in the ligament, tendon, and joint capsular tissues of rats and to identify the distribution of relaxin receptors in these tissues. Transverse carpal ligaments (TCLs), inguinal ligaments, anterior cruciate ligaments (ACLs), Achilles tendons, and shoulder joint capsules were obtained from male Wistar rats. Western blot analysis was used to identify relaxin receptor isoforms RXFP1 and RXFP2. The distribution of relaxin receptors was determined by immunohistochemical staining. The RXFP1 isoform was found in all tissues examined. The RXFP2 isoform was present in all tissues but the TCLs. Its expression in ACLs tissues was relatively weak compared to that in other tissues. Our results revealed that RXFP1 and RXFP2 were distributed in distinctly different patterns according to the type of tissue (vascular endothelial cells, fibroblast-like cells) they were identified.
authors.affiliation: Division of Physical Medicine and Rehabilitation, Department of Orthopaedic Surgery, Stanford University, Stanford, CA, USA.; Department of Physical Medicine & Rehabilitation, Eulji University Hospital and Eulji University School of Medicine, Daejeon, Korea.
authors.forename: Jae Hyung
authors.identifier: 0000-0002-7005-0113
authors.initials: JH
authors.lastname: Kim
authors.affiliation: Eulji Medi-Bio Research Institute, Daejeon, Korea .
authors.forename: Sang Kwang
authors.identifier: 0000-0001-8315-0458
authors.initials: SK
authors.lastname: Lee
authors.affiliation: Department of Biochemistry, Eulji University School of Medicine, Daejeon, Korea .
authors.forename: Seong Kyu
authors.identifier: 0000-0002-5446-3233
authors.initials: SK
authors.lastname: Lee
authors.affiliation: Department of Pathology, Eulji University School of Medicine, Daejeon, Korea .
authors.forename: Joo Heon
authors.identifier: 0000-0002-0999-4131
authors.initials: JH
authors.lastname: Kim
authors.affiliation: Division of Physical Medicine and Rehabilitation, Department of Orthopaedic Surgery, Stanford University, Stanford, CA, USA .
authors.forename: Michael
authors.identifier: 0000-0002-4827-9026
authors.initials: M
authors.lastname: Fredericson
mesh_terms: D000818:Animals; D015153:Blotting, Western; D005786:Gene Expression Regulation; D007150:Immunohistochemistry; D008022:Ligaments / Q000378:metabolism*; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D043562:Receptors, G-Protein-Coupled / Q000235:genetics* / Q000378:metabolism; D018000:Receptors, Peptide / Q000235:genetics* / Q000378:metabolism; D012785:Shoulder Joint / Q000378:metabolism*; D013710:Tendons / Q000378:metabolism*
chemical_list: D043562:Receptors, G-Protein-Coupled; D018000:Receptors, Peptide; C504789:Rxfp1 protein, rat; C511608:Rxfp2 protein, rat
keywords: Fibrosis; Joint Capsule; Ligament; Rat; Relaxin Receptor; Tendon