Related Experiment Video
Updated: Jun 14, 2026
Recapitulating Suckling-to-Weaning Transition In Vitro using Fetal Intestinal Organoids
Published on: November 15, 2019
Prenatal and postnatal differentiation of the small intestine in rat
Nadya I Penkova1, George A Baltadjiev, Yvetta A Koeva
1Department of Anatomy, Histology and Embryology, Medical University, Plovdiv, Bulgaria.
Insights
This study tracks rat small intestine development, observing beta-actin expression in smooth muscle and epithelial cells. Findings suggest mesenchymal and endodermal tissue interactions influence development.
Area of Science:
- Developmental Biology
- Gastroenterology
- Histology
Background:
- The gastrointestinal tract originates from endoblast and mesenchyme during prenatal development.
- Neuroectoblast cells also contribute to endocrine and neural structures within the gut.
Purpose of the Study:
- To investigate small intestine development in rat embryos and fetuses.
- To analyze beta-actin expression in epithelial and smooth muscle cells.
- To identify enteroendocrine EC cells using serotonin expression.
Main Methods:
- Studied rat embryos/fetuses (8-20 days gestation) and newborn rats.
- Employed hematoxylin-eosin staining, succinate dehydrogenase enzyme histochemistry.
- Utilized immunohistochemistry for beta-actin and serotonin.
Main Results:
- Early embryogenesis shows a primitive gut as an endoblastic tube with mesenchyme.
- Small intestine maturation is incomplete in newborns, with shallow crypts and sparse villi.
- Differentiated absorptive and enteroendocrine EC cells are present in the lining epithelium.
Conclusions:
- Observed beta-actin expression changes in smooth muscle and epithelial cells.
- These changes likely indicate inductive interference between mesenchymal and endodermal derivatives.
Unlabelled:
The gastrointestinal tract in the early prenatal development is an endoblastic mesenchyme-lined tube. The endoblast differentiates and gives origin to all epithelial structures (covering epithelium, glands). The mesenchyme develops into connective tissue, blood vessels, the smooth muscle cells of lamina muscularis mucosae and muscular tunic. Neuroectoblast cells participate in these processes--individual cells with future endocrine function, nerve cells and fibers that form nerve plexuses and vegetative ganglia. AIM OF THE PRESENT STUDY: To trace the changes in the small intestine development during the prenatal period in rat embryos and fetuses, and during the postnatal period in newborn rats. We specifically studied the beta-actin expression in the cytoskeletal structures of the covering epithelium and in the contractile elements of the differentiating smooth muscle cells. The presence and localization of the enteroendocrine EC cell was studied using the immunohistochemical expression of serotonin in them.
Material And Methods:
Material from rat embryos and fetuses aged 8-11, 12-15, 16-20 days of gestation and small intestine fragments from newborn rats was studied using routine hematoxylin-eosin staining, enzymohistochemically for succinate dehydrogenase and immunohistochemically for beta-actin and serotonin.
Results:
In the early embryogenesis (8-11 day of gestation), the primitive gut of rat embryos is an endoblastic tube of 2-3 layers of cuboidal cells covered with a thin layer of mesenchyme. In the subsequent stages of embryonic and fetal development the processes of differentiation run at different rates in the different tissues. The maturation process in the small intestine wall of one-day-old newborn rats is incomplete. The mucosa presents with shallow crypts and loosely set villi. Differentiated resorptive and enteroendocrine EC cells are found in the lining epithelium.
Conclusion:
The changes we found in the beta-actin expression in the contractile elements of the differentiating smooth muscle cells and the cytoskeletal structures of the lining epithelium probably reflect the induction interference between the derivatives of the mesenchyme and endoblast.
Related Concept Videos
01:23Renewal of Intestinal Stem Cells
01:27Histology of the Small Intestine
The intestinal lining features transverse folds called circular folds, each housing fingerlike projections known as intestinal villi. These villi are covered by a layer of simple columnar epithelium, also referred to as...
01:12Role Of Notch Signalling In Intestinal Stem Cell Renewal
Direct cell-to-cell contact is needed for the activation of Notch signaling. The signal is initiated when a notch ligand binds to a receptor on an adjacent cell, also...