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Relaxation of the mouse pubic symphysis during late pregnancy is not accompanied by the influx of granulocytes
Author(s) -
Rosa Renata Giardini,
Tarsitano Christiane Aparecida Badin,
Hyslop Stephen,
Yamada Áureo Tatsumi,
Toledo Olga Maria S.,
Joazeiro Paulo Pinto
Publication year - 2008
Publication title -
microscopy research and technique
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.536
H-Index - 118
eISSN - 1097-0029
pISSN - 1059-910X
DOI - 10.1002/jemt.20549
Subject(s) - pubic symphysis , pregnancy , stromal cell , extracellular matrix , biology , andrology , pathology , medicine , anatomy , microbiology and biotechnology , pelvis , genetics
In some animals, such as mice and guinea pigs, a hormonally controlled mechanism increases the flexibility of the pubic symphysis and enhances the cervical remodeling necessary for safe delivery. Cervical ripening during pregnancy is associated with a paradoxical influx of leukocytes. However, the changes in cell metabolism during relaxation of the mouse pubic symphysis for delivery have not been extensively studied. In this work, we used light microscopy and transmission and scanning electron microcopy, as well as immunohistochemistry and Western blotting for MMP‐8, to investigate the involvement of granulocytes or resident stromal cells in the relaxation of the virgin pubic symphysis during late pregnancy (days 18 and 19, before delivery) in vivo and in explanted joints. MMP‐8 was studied because this collagenase is a hallmark for cervical ripening associated with the influx of granulocytes during late pregnancy. Extensive dissolution and disorganization of the extracellular matrix was seen around fibroblastic‐like cells in late pregnancy. In contrast to the cervix (positive control), morphological and immunohistochemical analyses revealed that there was no characteristic cellular inflammatory response in the interpubic tissue. Staining for MMP‐8 was observed in chondroid and fibroblastic‐like cells of virgin and relaxed interpubic ligament, respectively. However, no granulocytes were seen during the extensive remodeling of the pubic joint in late pregnancy. These results indicate that constitutive stromal cells may have an important role in tissue relaxation during remodeling of the pubic symphysis in pregnancy. Microsc. Res. Tech., 2008. © 2007 Wiley‐Liss, Inc.