Evaluating residual strain throughout the murine female reproductive system

Abstract

Mounting evidence suggests that cells within soft tissues seek to maintain a preferred biomechanical state. Residual stress is defined as the stress that remains in a tissue when all external loads are removed and contributes to tissue mechanohomeostasis via decreasing the transmural gradient of wall stress. Current computational models of pelvic floor mechanics, however, often do not consider residual stress. Residual strain, a result of residual stress can be quantitatively measured through opening angle experiments. Therefore, the objective of this study is to quantify the regional variations in opening angles along the murine female reproductive system at estrus and diestrus to quantify residual strain in the maintenance state of sexually mature females. Further, evidence suggests that hydrophilic glycosaminoglycan/proteoglycans are integral to cervical remodeling. Thus, variations in opening angles following hypo-osmotic loading are evaluated. Opening angle experiments were performed along the murine reproductive system in estrus (n = 8) and diestrus (n = 8) and placed in hypo-osmotic solution. Measurements of thickness and volume were also obtained for each group. Differences in opening angle were observed with respect to region and loading (p < 0.05), however, no differences with respect to estrus stage were significant. Thickness values were significant with respect to region, (p < 0.05) only. The effects of both estrous cycle and region (p < 0.05) resulted in significant differences in observed volume. The observed regional differences indicate changes in the stress-free state of each tissue which may have implications for future computational models to advance women’s reproductive health.

Growth-profile configuration for specific deformations of tubular organs: A study of growth-induced thinning and dilation of the human cervix

“…Besides thinning and dilation, the cervix also shortens and forms a “V” shape over its top boundary [ 61 ]. Buckling of the inner surface may also happen under growth [ 62 , 63 ], residual stress can occur in the cervix reference configuration [ 64 ], and cervical muscle also contracts during gestation [ 65 ]. These factors are not included in the current study.…”

Comparison of Biaxial Biomechanical Properties of Post-menopausal Human Prolapsed and Non-prolapsed Uterosacral Ligament

“…3E,F) for the quantification of collagen orientation, alignment, and straightness ratio 17,45 . To quantify the SMC and collagen area fractions, MTC images were analysed with ImageJ's (National Institutes of Health, Bethesda, MD, USA) open source colour deconvolution plug-in 45,46 and an open source GNU image manipulation program (GIMP) 45,[47][48][49] . The previously established colour deconvolution used herein is capable of separating the colours in their red, blue and green absorption characteristics [45][46][47] .…”

Pelvic Organ Prolapse: A Review of In Vitro Testing of Pelvic Support Mechanisms

“… 52 Residual stress describes the stress existing within intact tissue without external forces acting on the tissue, 52 whereas residual strain is the deformation induced by the release of the residual stress as a result of disruption of the tissue wall. 46 , 52 , 76 Considering female reproductive organs and estrous cycle, Capone et al quantified the differences in residual strain throughout the murine reproductive tract. 76 The vagina, in comparison to the cervix and uterus, had the largest surface area and greatest amount of collagen.…”

“… 46 , 52 , 76 Considering female reproductive organs and estrous cycle, Capone et al quantified the differences in residual strain throughout the murine reproductive tract. 76 The vagina, in comparison to the cervix and uterus, had the largest surface area and greatest amount of collagen. Thus, residual strain was greater in the vagina vs the cervix and uterus, suggesting a gradient of mechanical properties through the reproductive tract.…”

“…Thus, residual strain was greater in the vagina vs the cervix and uterus, suggesting a gradient of mechanical properties through the reproductive tract. 76 …”