Related Experiment Video
Updated: Aug 12, 2026
A System for ex vivo Culturing of Embryonic Pancreas
Published on: August 27, 2012
Pancreatic morphogenesis and extracellular matrix organization during rat development
M Hisaoka1, J Haratake, H Hashimoto
1Department of Pathology and Oncology, School of Medicine, University of Occupational and Environmental Health, Kitakyushu, Japan.
Insights
This study reveals how extracellular matrix organization changes during rat pancreas development, impacting branching morphogenesis and endocrine cell differentiation. Key alterations in collagen and fibronectin precede acinar cell formation.
Area of Science:
- Developmental Biology
- Cell Biology
- Histology
Background:
- Pancreatic development involves complex morphogenetic processes.
- Extracellular matrix (ECM) plays a crucial role in tissue development and differentiation.
- Understanding ECM dynamics is key to deciphering pancreatic morphogenesis.
Purpose of the Study:
- To investigate the chronological changes in rat pancreatic morphology and ECM organization in vivo.
- To elucidate the relationship between ECM alterations and pancreatic epithelial morphogenesis.
- To explore the role of ECM in epithelial-mesenchymal interactions during endocrine cell differentiation.
Main Methods:
- Morphological analysis of rat pancreata from 12 days gestation to neonatal stage.
- Ultrastructural examination of basal lamina and epithelial-mesenchymal contacts.
- Immunohistochemical localization of ECM components including fibronectin, collagen types I, III, and IV, and laminin.
Main Results:
- Rat pancreas development stages identified: epithelial buds, branching, tubular, and acinar structures.
- Basal lamina disruptions observed at early stages facilitated epithelial-mesenchymal contact.
- Collagen fibrils and fibronectin accumulated at branching points, while laminin and collagen IV showed linear localization.
- Collagen type III and diffuse fibronectin/collagen I were prominent in later stages and postnatally.
Conclusions:
- Dynamic changes in ECM organization, particularly collagen and fibronectin, are closely linked to rat pancreatic morphogenesis, especially branching.
- ECM alterations precede distinct acinar cell differentiation.
- Epithelial-mesenchymal interactions, mediated by ECM, are crucial for endocrine cell development.
Abstract:
We investigated the rat pancreatic morphology at various developmental stages ranging from 12 days of gestation to the neonatal stage, with special emphasis on alterations in extracellular matrix organization in vivo. The rat pancreatic development in utero could be divided into four representative stages as follows: (1) initial epithelial buds (12 days of gestation), (2) elongated and branching epithelium (13-14 days), (3) tubular structure (15-16 days), and (4) acinar structure (17 days or more). Ultrastructurally, the fetal and neonatal pancreata were almost constantly encompassed by continuous basal lamina, except for the earliest stage, in which minute disruptions of basal lamina were observed. Through the disruption, the direct epithelial-mesenchymal contact was formed between an endocrine cell and an adjacent mesenchymal cell, which implied epithelial-mesenchymal interactions in processes of endocrine cell differentiation. Collagen fibrils were frequently accumulated at the cleft (branchpoint) of the branching epithelium during the second and third stages mentioned above. Immunohistochemically, fibronectin and collagen type-I were localized particularly beside the neck (narrow part) or cleft of the pancreatic epithelium at these stages, although continuous linear localization of these matrices was noted around the initial pancreatic bud. This was in contrast to invariable linear localization of laminin and collagen type-IV at the epithelial/mesenchymal interface throughout the pancreatic development. Diffuse fibrillar localization of fibronectin and collagen type-I in the mesenchyme was pronounced at the later stages and after birth. Collagen type-III was only focally detectable around the pancreatic epithelium from the second stage, and its distinct localization was noted in the interlobular connective tissue after birth. Thus, chronological changes in extracellular matrix organization seemed to be closely related to morphogenetic processes of the rat pancreas, especially in the branching epithelial morphogenesis, and the major alterations appeared prior to distinct acinar cell differentiation.
