Effects of relaxin, pregnancy and parturition on collagen metabolism in the rat pubic symphysis

Abstract

The aim of this study was to examine the changes in collagen metabolism that occur during pregnancy and parturition and upon relaxin administration to the rat pubic symphysial interpubic tissue. Pubic symphyses were collected from non-pregnant, and intact and ovariectomised pregnant Sprague-Dawley rats at days 15, 18 and 21 of pregnancy as well as during and after delivery, and analysed for collagen content and solubility. SDS-PAGE was used to determine collagen composition. During pregnancy and particularly during birth, there was a significant reduction in both the tissue wet (57 3%) and dry (43 3%) weight (n=7), which coincided with a significant increase in water content (to 80%) and was attributed to a significant (P<0·05) reduction in overall tissue collagen content (by 47 2%). This resulted in both soluble (10%) and insoluble (90%) collagen levels being reduced, but gel electrophoresis demonstrated the presence of types I, II and V collagen in all samples. Western blot analysis confirmed the presence of type II collagen throughout pregnancy, confirming that the rat pubic symphysis remained a fibrocartilaginous tissue throughout gestation. In the absence of the ovaries and hence relaxin, tissue collagen content and solubility were not significantly different from control measurements. However, tissues of ovariectomised animals treated with oestrogen and progesterone (pellets) and relaxin (injection) contained collagen levels that mimicked those of late pregnancy and parturition. These results suggest that relaxin plays an important role in regulating collagen catabolism during gestation in the rat.

Are there early signs that predict development of temporomandibular joint disease?

“…The preponderance of women in the present study is consistent with previous findings (6). Attempts to explain female dominance among TMJD patients have identified several potential predisposing factors, including the effects of gonadal hormones such as estrogen, progesterone, and relaxin (17,18). These hormones are believed to have a degenerative effect on the disc and/or bone of the mandibular condyle.…”

A prospective cohort study of digital cushion and corium thickness. Part 1: Associations with body condition, lesion incidence, and proximity to calving

“…This could be an effect of peri-parturient hormones, such as relaxin (Tarlton et al, 2002) or estrogens. Relaxin, for example, mediates distension of the reproductive tract for parturition by activating metalloproteinases that degrade collagen and is known to have effects on other structures throughout the body (Samuel et al, 1998); if it acts upon the suspensory apparatus it could cause the distal phalanx to sit lower in the hoof around calving. In previous work assessing the thickness of the sole soft tissues in a cross-sectional study, the nadir of sole soft tissue thickness was observed at approximately 120 DIM and corresponded with the nadir of BCS (Bicalho et al, 2009).…”

Collagen- vs. Gelatine-Based Biomaterials and Their Biocompatibility: Review and Perspectives

“…Types IX, XI, XII and XIV are fibril associated collagens with small chains, which contain some non-helical domains. Type VI is microfibrillar collagen and type VII is anchoring fibril collagen (Samuel et al, 1998). Fig.…”