Extracellular breakdown of collagen by mice decidual cells. A cytochemical and ultrastructural study

The interaction of antimesometrial decidual cells and collagen fibrils was studied by light microscopy and ultrastructural cytochemistry in fed and acutely fasted mice on days 9-11 of pregnancy. Fibrillar elements in the extracellular space consisted of collagen fibrils and filamentous aggregates (disintegrating collagen fibrils). Intracellular vacuoles exhibited typical collagen immersed in electron-translucent material (clear vacuoles) and faint cross-banded collagen immersed in electron-opaque material (dark vacuoles). Fibrillar elements showed extracellular acid phosphatase activity which was stronger in the region of mature decidua than in predecidual cells region in all animals; it was conspicuous in mature decidua of fasted animals. Intracellular acid phosphatase activity was observed in dark vacuoles and lysosomes, and was absent in clear vacuoles in all cells studied. Since acid phosphatase activity reflects the presence of lysosomal hydrolases in general, the results indicate that breakdown of extracellular collagen occurs by release of lysosomal enzymes by decidual cells and also by internalization of collagen for intracellular degradation in fed and fasted mice. Collagen breakdown may be part of the process of tissue remodeling in mature and predecidual regions, however, in mature decidua, collagen breakdown is enhanced and may therefore contribute to nutrition of the fetus, specially in acutely fasted mice.

Expression of nuclear factor-kappaB in mouse uterus during peri-implantation / 华中科技大学学报（医学）（英德文版）

To investigate the expression of the subunit p65 of NF-kappaB and inhibitor kappa B alpha (IkappaBalpha) in mouse uterus during peri-implantation, thereby investigating whether transient activation of nuclear factor-kappaB (NF-kappaB) takes place during embryo implantation in mice. Immunohistochemical technique was used to examine the expression and localization of p65 in endometrium or deciduas, and Western blot analysis was employed to detect the levels of IkappaBalpha protein in mouse endometrium or deciduas. P65 protein was detected in stromal cells, epithelial cells of endometrium as well as in myometrium. Staining was predominately seen in the cytoplasm of the cells. Staining intensity for p65 was stronger in the epithelial compartment than the stromal compartment and myometrium. Staining intensity increased slightly during pregnancy, and it reached a high level on pregnancy day 5 and day 8. In contrast to p65, the level of IkappaBalpha protein was lowest on pregnancy day 5 in all groups. Our results suggested that NF-kappaB may regulate embryo implantation by its transient activation in mice.

Efecto de la hormona liberadora de tirotrofina en la secreción de prolactina de decidua humana / Effect of thyrotropin releasing hormone in the prolactin secretion of human decidua

Para prevenir el síndrome de distress respiratorio (RDS), se ha usado el tratamiento conjunto de betametasona y hormona liberadora de tirotrofina (TRH). La TRH actuaría indirectamente sobre la producción del surfactante pulmonar, estimulando la secreción de hormonas tiroídeas; otra vía para incrementar el surfactante pulmonar es induciendo la secreción de PRL Prolactina (un potente estimulador de la secreción del surfactante pulmonar) desde la hipófisis o de otros tejidos que secreten PRL (como se ha descrito previamente para la decidua). El objetivo de este trabajo fue estudiar el efecto de diferentes dosis de TRH en la secreción de PRL por el tejido corión-decidua y caracterizar las formas bioactivas de PRL secretada por dicho tejido. Veinte placentas de embarazos normales (38-41 semenas), obtenidas por parto normal o cesáreas, fueron recolectadas en el Departamento de Obstetricia y Ginecología del Hospital Clínico de la Universidad de chile. Explantes de tejido corión-decidua secretaron PRL en condiciones basales, con una secreción máxima de la hormona a las 24 horas de incubación. Se encontró un aumento significativo (p<0,05) en la secreción de PRL con 1,5 x 10 elevado 8 M de TRH, el cual fue debido principalmente a un aumento significativo (p<0,05) de la forma little del PRL bioactivo. Estos resultados sugieren que una de las maneras en que TRH acelere la madurez pulmonar fetal podría ser aumentando la secreción de PRL por el tejido decidual; esta hormona podría pasar rápidamente al líquido amniótico para activar la producción del surfactante pulmonar del feto

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

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 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.