Phenotypic modulation of fibroblastic cells in the mucous layer of the human uterine cervix at term.

The uterine cervix is a dynamic structure with a high capacity to adapt to different, even opposing, roles during the sequence of physiological events of gestation (for example, acting as a barrier to retain the fetus during pregnancy and dilating to allow delivery at term). Histoarchitectural changes of the uterine cervix allow its successful adaptation. The aim of this study was to investigate whether fibroblastic cell plasticity, described in the lamina propria of the rat uterine cervix at term, could be observed in women too. Biopsy specimens of non-pregnant and intrapartum human cervices were studied under the transmission electron microscope, and cytoskeletal differentiation markers were identified by immunohistochemistry under the light microscope. Desmin-positive cells were present in the mucous layer of the cervix during labour. These cells displayed cytoplasmic processes (typical of myofibroblasts) that also stained positively for vimentin. The main ultrastructural features for defining the myofibroblast under the electron microscope were also observed in these cells. However, cervices of non-pregnant women contained resident fibroblasts at the same location. Examination of the differentiation repertoire of fibroblastic cells in the mucous layer of the uterine cervix resulted in the characterization of myofibroblasts at term. The implications of the plasticity of fibroblastic-myofibroblastic cells in the physiological changes displayed in the uterine cervix during pregnancy, labour and postpartum involution require further investigation.