Related Experiment Video
Updated: Sep 23, 2026

Surgical Retrieval, Isolation and In vitro Expansion of Human Anterior Cruciate Ligament-derived Cells for Tissue Engineering Applications
Published on: April 30, 2014
Relaxin receptors in the human female anterior cruciate ligament
Jason L Dragoo1, Richard S Lee, Prosper Benhaim
1Department of Orthopaedic Surgery, University of California Los Angeles School of Medicine, Los Angeles, California 90095, USA.
Background:
Noncontact anterior cruciate ligament injuries occur two to eight times more often in women than in men. Changes in ligament laxity and strength have been associated with female hormones such as relaxin.
Hypothesis:
Relaxin receptors are present within the female anterior cruciate ligament.
Study Design:
Controlled laboratory study.
Methods:
Remnants of anterior cruciate ligament were harvested from five women and five men undergoing routine ligament reconstruction. Relaxin was biotinylated and analyzed for biologic activity with use of the mouse interpubic ligament bioassay. Immunohistochemical localization of relaxin receptors was performed with appropriate negative controls and competitive binding assays to determine receptor specificity and saturability.
Results:
Anterior cruciate ligament sections from women but not from men showed uniform specific binding that was limited to synovial lining cells, stromal fibroblasts, and cells lining blood vessels. Specific binding was confirmed in the presence of a 2000-fold excess of human insulin, the structural homolog of relaxin, and competitive inhibition was demonstrated in the presence of a 2000-fold excess of unlabeled relaxin.
Conclusions:
Relaxin exhibits specific saturable binding in the female anterior cruciate ligament, where specific relaxin receptors were present.
Clinical Relevance:
The high incidence of anterior cruciate ligament rupture in female athletes may be partially explained by the effects of relaxin.
More Related Videos
06:27Non-Invasive Compression-Induced Anterior Cruciate Ligament (ACL) Injury and In Vivo Imaging of Protease Activity in Mice
Published on: September 29, 2023
06:28Anterior Cruciate Ligament Transection and Synovial Fluid Lavage in a Rodent Model to Study Joint Inflammation and Posttraumatic Osteoarthritis
Published on: September 2, 2025
Related Concept Videos
Relaxation of Skeletal Muscles
When an action potential reaches the axon terminal, it depolarizes the membrane and opens voltage-gated sodium channels. Sodium ions enter the cell, further depolarizing the presynaptic membrane. This depolarization causes voltage-gated calcium channels to open.
Transducer Mechanism: G Protein–Coupled Receptors
GPCRs are also called heptahelical, 7TM, or...
Ligand-Gated Ion Channel Receptor: Gating Mechanism