Relaxin Receptor RXFP1 and RXFP2 Expression in Ligament, Tendon, and Shoulder Joint Capsule of Rats

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.

Relationship between pelvic floor dysfunction and serum relaxin H2 and expression of vaginal wall relaxin receptor LGR7 mRBA in late pregnant women / 上海交通大学学报（医学版）

Objective To investigate the relationship between pelvic floor dysfunction and serum relaxin H2 and expression of vaginal wall relaxin receptor LGR7 mRNA in late pregnant women. Methods Before the beginning of delivery,all women were evaluated by pelvic organ prolapse quantitation(POP-Q)scoring.Twelve women with stress urinary incontinence(SUI)and stage II prolapse of anterior vaginal wall were selected as patient group,and another 24 women without SUI and prolapse of pelvic floor were served as control group.Serum relaxin H2 was determined by ELISA.Vaginal wall tissues were taken after vaginal delivery,and the expression of relaxin receptor LGR7 mRNA was detected by RT-PCR.Results The serum level of relaxin H2 and expression of LGR7 mRNA of vaginal tissues in patient group were significantly higher than those in control group(P<0.01,P<0.05). Conclusion The increased level of serum relaxin and expression of vaginal wall relaxin receptor may correlate with the pelvic floor dysfunction in late pregnant women.

Role of relaxin in heart disease and therapeutic potential / 西安交通大学学报(医学版)

Following a brief introduction of relaxin family members, receptors and related signalling pathways,we review effects of relaxin on cardiovascular system,particularly,its anti-fibrotic action.The heart and vessels are target organs of relaxin.Recent studies have documented that the relaxin genes are upregulated in the diseased heart of humans and experimental animals.In several animal disease models,relaxin can reverse cardiac fibrosis.Relaxin may also indirectly promote myocardial regeneration and repair by suppressing fibrotic healing.Further research needs to focus on elucidating the exact mechanisms utilized by relaxin to induce these cardiac actions and translation of experimental findings to novel therapy of cardiovascular disease.