Tear propagation in vaginal tissue under inflation.

Autor: McGuire JA; STRETCH Lab, Department of Biomedical Engineering and Mechanics, Virginia Tech, Blacksburg, VA 24061, United States., Monclova JL; STRETCH Lab, Department of Biomedical Engineering and Mechanics, Virginia Tech, Blacksburg, VA 24061, United States., Coariti ACS; PROBE Lab, School of Engineering, Brown University, Providence, RI 02912, United States., Stine CA; Department of Biomedical Engineering and Mechanics, Virginia Tech, Blacksburg, VA 24061, United States., Toussaint KC Jr; PROBE Lab, School of Engineering, Brown University, Providence, RI 02912, United States., Munson JM; Department of Biomedical Engineering and Mechanics, Virginia Tech, Blacksburg, VA 24061, United States., Dillard DA; Department of Biomedical Engineering and Mechanics, Virginia Tech, Blacksburg, VA 24061, United States., De Vita R; STRETCH Lab, Department of Biomedical Engineering and Mechanics, Virginia Tech, Blacksburg, VA 24061, United States. Electronic address: devita@vt.edu.
Jazyk: angličtina
Zdroj: Acta biomaterialia [Acta Biomater] 2021 Jun; Vol. 127, pp. 193-204. Date of Electronic Publication: 2021 Apr 06.
DOI: 10.1016/j.actbio.2021.03.065
Abstrakt: Vaginal tearing at childbirth is extremely common yet understudied despite the long-term serious consequences on women's health. The mechanisms of vaginal tearing remain unknown, and their knowledge could lead to the development of transformative prevention and treatment techniques for maternal injury. In this study, whole rat vaginas with pre-imposed elliptical tears oriented along the axial direction of the organs were pressurized using a custom-built inflation setup, producing large tear propagation. Large deformations of tears through propagation were analyzed, and nonlinear strains around tears were calculated using the digital image correlation technique. Second harmonic generation microscopy was used to examine collagen fiber organization in mechanically untested and tested vaginal specimens. Tears became increasingly circular under pressure, propagating slowly up to the maximum pressure and then more rapidly. Hoop strains were significantly larger than axial strains and displayed a region- and orientation-dependent response with tear propagation. Imaging revealed initially disorganized collagen fibers that aligned along the axial direction with increasing pressure. Fibers in the near-regions of tear tips aligned toward the hoop direction, hampering tear propagation. Changes in tear geometry, regional strains, and fiber orientation revealed the inherent toughening mechanisms of the vaginal tissue. STATEMENT OF SIGNIFICANCE: Women's reproductive health has historically been understudied despite alarming maternal injury and mortality rates in the world. Maternal injury and disability can be reduced by advancing our limited understanding of the large deformations experienced by women's reproductive organs. This manuscript presents, for the first time, the mechanics of tear propagation in vaginal tissue and changes to the underlying collagen microstructure near to and far from the tear. A novel inflation setup capable of maintaining the in vivo tubular geometry of the vagina while propagating a pre-imposed tear was developed. Toughening mechanisms of the vagina to propagation were examined through measurements of tear geometry, strain distributions, and reorientation of collagen fibers. This research draws from current advances in the engineering science and mechanics fields with the goal of improving maternal health care.
Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
(Copyright © 2021 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.)
Databáze: MEDLINE
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