Early growth response factor-1: expression in a rabbit flexor tendon scar model

Area of Science:

• Orthopedic Surgery
• Regenerative Medicine
• Molecular Biology

Background:

• Adhesion formation after flexor tendon repair impedes functional recovery.
• Growth factors play a role in adhesion scar development.
• Early growth response factor-1 (EGR-1) is a transcription factor linked to fibrosis and extracellular matrix gene expression.

Purpose of the Study:

• To investigate the expression of EGR-1 in a rabbit flexor tendon repair model.
• To determine the role of EGR-1 in tendon adhesion formation.
• To evaluate the effect of sodium morrhuate on EGR-1 expression and adhesion.

Main Methods:

• Flexor digitorum profundus tendons in zone II of rabbit forepaws were lacerated and repaired.
• Sodium morrhuate or phosphate-buffered saline was applied topically to the repair site.
• Tendon tissues were harvested at various postoperative intervals (1-28 days) and analyzed using immunohistochemistry and Masson trichrome staining.

Main Results:

• EGR-1 was expressed at the tendon repair site, along the epitenon, and in inflammatory cells within the scar matrix.
• Baseline EGR-1 expression was observed in epitenon cells of unoperated tendons.
• EGR-1 expression peaked at postoperative day 7.
• No significant difference in adhesion scar formation was observed between sodium morrhuate and phosphate-buffered saline treatment groups.

Conclusions:

• EGR-1 expression is elevated in the tendon wound environment after repair.
• Normal epitenon cells exhibit low baseline EGR-1 levels.
• Sodium morrhuate did not enhance scar matrix production compared to the control.