Relaxin and β-estradiol modulate targeted matrix degradation in specific synovial joint fibrocartilages: progesterone prevents matrix loss

作者：Gihan Hashem, Qin Zhang, Takayuki Hayami, Jean Chen, Wei Wang, Sunil Kapila · 发表于：Arthritis Research & Therapy · 年份：2006 · DOI：10.1186/ar1978 · 被引用次数：94 · 研究领域：Pregnancy-related medical research、Lower Extremity Biomechanics and Pathologies

Relaxin, a 6-kDa polypeptide hormone, is a potent mediator of matrix turnover and contributes to the loss of collagen and glycosaminoglycans (GAGs) from reproductive tissues, including the fibrocartilaginous pubic symphysis of several species. This effect is often potentiated by beta-estradiol. We postulated that relaxin and beta-estradiol might similarly contribute to the enhanced degradation of matrices in fibrocartilaginous tissues from synovial joints, which may help explain the preponderance of diseases of specific fibrocartilaginous joints in women of reproductive age. The objective of this study was to compare the in vivo effects of relaxin, beta-estradiol, and progesterone alone or in various combinations on GAG and collagen content of the rabbit temporomandibular joint (TMJ) disc fibrocartilage, knee meniscus fibrocartilage, knee articular cartilage, and the pubic symphysis. Sham-operated or ovariectomized female rabbits were administered beta-estradiol (20 ng/kg body weight), progesterone (5 mg/kg), or saline intramuscularly. This was repeated 2 days later and followed by subcutaneous implantation of osmotic pumps containing relaxin (23.3 microg/kg) or saline. Tissues were retrieved 4 days later and analyzed for GAG and collagen. Serum relaxin levels were assayed using enzyme-linked immunosorbent assay. Relaxin administration resulted in a 30-fold significant (p < 0.0001) increase in median levels (range, approximately 38 to 58 pg/ml) of systemic relaxin. Beta-estra...