Combination of histochemical analyses and micro-MRI reveals regional changes of the murine cervix in preparation for labor

Abstract

The cervix is responsible for maintaining pregnancy, and its timely remodeling is essential for the proper delivery of a baby. Cervical insufficiency, or “weakness”, may lead to preterm birth, which causes infant morbidities and mortalities worldwide. We used a mouse model of pregnancy and term labor, to examine the cervical structure by histology (Masson Trichome and Picrosirius Red staining), immunohistochemistry (Hyaluronic Acid Binding Protein/HABP), and ex-vivo MRI (T2-weighted and diffusion tensor imaging), focusing on two regions of the cervix (i.e., endocervix and ectocervix). Our results show that mouse endocervix has a higher proportion of smooth muscle cells and collagen fibers per area, with more compact tissue structure, than the ectocervix. With advanced gestation, endocervical changes, indicative of impending delivery, are manifested in fewer smooth muscle cells, expansion of the extracellular space, and lower presence of collagen fibers. MRI detected three distinctive zones in pregnant mouse endocervix: (1) inner collagenous layer, (2) middle circular muscular layer, and (3) outer longitudinal muscular layer. Diffusion MRI images detected changes in tissue organization as gestation progressed suggesting the potential application of this technique to non-invasively monitor cervical changes that precede the onset of labor in women at risk for preterm delivery.

Early Magnetic Resonance Imaging Measurements and Prediction of Second Trimester Pregnancy Loss: a Nomogram Model Analysis

“… 28 , 29 A recent study has shown diffusion MRI images detected changes in tissue organization as gestation progressed suggesting the potential application of this technique to non-invasively monitor cervical changes that precede the onset of labor in women at risk for preterm delivery. 14 Our study is concordant with existing research indicating that MRI is a promising tool to assess the cervix. Women experiencing second-trimester miscarriage are at increased risk in subsequent pregnancies of recurrence.…”

“… 13 Through signal intensity spectroscopy, accurate assessment of the biometry, and individualization of the stromal zone, MRI of the cervix has shown particular morphological features that may signify access to the cervix’s microstructure. 14 In this aspect, exploration of the potential risk factors contributing to miscarriage prior to conception and further setting up of a predictive calculation model with a combination of all the risk factors will be of great importance.…”