Branching morphogenesis in the embryonic mouse submandibular gland: a scanning electron microscopic study

Area of Science:

• Developmental Biology
• Histology
• Cell Biology

Background:

• Salivary gland development is complex, involving intricate epithelial-mesenchymal interactions.
• Previous scanning electron microscopy (SEM) studies were limited by surrounding mesenchymal tissue, hindering detailed observation of submandibular gland morphogenesis.

Purpose of the Study:

• To investigate the early morphogenetic events of mouse submandibular gland branching.
• To overcome limitations of traditional SEM by employing enzymatic digestion for clearer visualization of epithelial structures.

Main Methods:

• Application of a modified Evan's enzymatic digestion technique to embryonic mouse submandibular glands.
• High-resolution scanning electron microscopy (SEM) for detailed morphological analysis.

Main Results:

• Identified pit and shallow cleft formations on the lateral aspect of the spherical end bud.
• These structures are proposed as the initial epithelial movements establishing primary branchings.
• Observed developmental changes in cell projections on the basal epithelial surface, suggesting roles in epithelial-mesenchymal contacts.

Conclusions:

• The modified enzymatic digestion method effectively reveals key early branching events in submandibular gland development.
• Epithelial invaginations (pits and clefts) are critical for initiating salivary gland branching.
• Further investigation into epithelial cell projections offers insights into epithelial-mesenchymal signaling during gland formation.