Regional Differences following Partial Salivary Gland Resection.

Area of Science:

• Regenerative Medicine
• Tissue Repair and Regeneration
• Mammalian Organ Physiology

Background:

• Partial organ resection is a clinical strategy and research model for studying tissue repair.
• Salivary glands (SGs) possess regenerative potential, but mechanisms underlying repair and potential failure are not fully understood.
• Investigating injury responses in SGs can reveal insights applicable to broader regenerative medicine.

Purpose of the Study:

• To establish a murine submandibular salivary gland (SMG) partial resection model for studying repair mechanisms.
• To analyze molecular and cellular changes following partial sialoadenectomy over 56 days.
• To differentiate between normal wound healing and aberrant fibrotic responses within the same organ.

Main Methods:

• Murine submandibular salivary gland (SMG) partial resection (sialoadenectomy).
• Whole-gland measurements, microarray analysis for transcriptome changes, and quantitative immunohistochemistry (IHC) for protein expression (e.g., Ki67, M2 macrophages).
• Longitudinal analysis over 56 days post-injury.

Main Results:

• Partial SMG resection induced dynamic transcriptome changes within 3 days, resolving by day 14, with signatures for cell cycle, inflammation, and extracellular matrix (ECM) remodeling.
• A transient, gland-wide proliferative response (Ki67+) in epithelial and stromal cells occurred from day 3 to day 14.
• A distinct region exhibited a sustained fibrotic response with increased ECM deposition, persistent stromal cell proliferation, and M2 macrophage presence through day 56.

Conclusions:

• The partial SMG resection model effectively demonstrates both normal healing and aberrant fibrotic responses within the same tissue.
• Understanding the regional differences in wound healing is crucial for developing effective regenerative therapies.
• This model can uncover mechanisms that impede mammalian wound healing and regeneration.