Autoradiography reveals regional metabolic differences in the endometrium of pregnant and nonpregnant mice

Abstract

The rodent endometrium undergoes remarkable modifications during pregnancy, resulting from a redifferentiation of its fibroblasts. During this modification (decidualization), the fibroblasts transform into large, polyhedral cells that establish intercellular junctions. Decidualization proceeds from the subepithelial stroma towards the deep stroma situated next to the myometrium and creates regions composed of cells in different stages of differentiation. We studied by autoradiography whether cells of these different regions have different levels of macromolecular synthesis. Radioactive amino acids or radioactive sulfate were administered to mice during estrus or on different days of pregnancy. The animals were killed 30 min after injection of the precursors and the uteri were processed for light microscope autoradiography. Silver grains were counted over cells of different regions of the endometrium and are reported as the number of silver grains per area. Higher levels of incorporation of amino acids were found in pregnant animals as compared to animals in estrus. In pregnant animals, the region of decidual cells or the region of fibroblasts transforming into decidual cells showed the highest levels of synthesis. Radioactive sulfate incorporation, on the other hand, was generally higher in nonpregnant animals. Animals without decidual cell transformation (nonpregnant and 4th day of pregnancy) showed a differential incorporation by subepithelial and deep stroma fibroblasts. This study shows that regional differences in synthetic activity exist in cells that are in different stages of transformation into decidual cells as well as in different regions of the endometrium of nonpregnant mice. Correspondence T.M.T. Zorn

Mapping of estradiol binding sites through receptor micro-autoradiography in the endometrial stroma of early pregnant mice

“…In the human endometrium, estrogen and progesterone receptors are also differently expressed in the basal and functional layers (Coppens et al 1993;Critchley et al 2001). These results reinforce previous studies from our group showing that the mouse endometrium presents a compartmentalization similar to that of the human endometrium (Oliveira et al 1995(Oliveira et al , 1998Zorn et al 1995;Greca et al 1998;Salgado et al 2009aSalgado et al , b, 2011Salgado et al , 2013Favaro et al 2014). While the superficial stroma (functional layer in humans) commits with decidualization, the deep stroma (basal layer) remains undifferentiated and contributes to reconstruct the endometrium after pregnancy (Abrahamsohn 1983; Kleinfeld and O'Shea 1983;Favaro et al 2014;Cao et al 2015).…”

“…Accordingly, hormone-dependent changes such as cell proliferation, differentiation, and establishment of specific metabolic patterns occur in all compartments of the uterus. The estrogen-dependent nature of these events has been related to estrogen receptor levels in the cells (Stumpf 1968;Ward et al 1978;Tibbetts et al 1998;Oliveira et al 1995Oliveira et al , 1998Zorn et al 1995Zorn et al , 2003Tessier et al 2000).…”

Estradiol induces transcriptional and posttranscriptional modifications in versican expression in the mouse uterus

“…We infer that ovariectomy doesn’t entirely suppress the stimulus on versican expression due to a basal hormonal modulation from other sources, such as the adrenal gland. It is worth mentioning that there is a clear compartmentalization of the endometrial stroma into superficial and deep regions, formed by genetically distinct cell populations (Oliveira et al 1998; Zorn et al 2003). The difference in the immunodeposition pattern observed between both doses is certainly due to a dose-dependent effect of E2 on versican expression.…”

Distribution of laminin, vimentin and desmin in the rat uterus during initial stages of implantation

“…Five different zones can be distinguished with decidualization in the pseudo pregnant rat endometrium: I-Basal zone, II-the capsule, III-the antimesometrial deciduoma, IV-mesometrial deciduoma; and V-glycogenic area (O'Shea et al 1983). Decidualization proceeds from the sub epithelial stroma towards the deep stroma situated next to the myometrium and creates regions composed of cells in different stages of differentiation (Oliveira et al 1998). The mature decidual cells are large polygonal shaped and multinucleated with accumulated organelles that are associated with the synthesis of macro-molecules, Intermediate filaments (Ifs) and eventually lipid droplets and glycogen (Abrahamsohn and Zorn 1993).…”