Effect of rapamycin on wound healing: an experimental study

Area of Science:

• Surgical Innovation
• Wound Healing Research
• Pharmacological Studies

Background:

• Understanding the molecular mechanisms of wound healing is crucial for improving surgical outcomes.
• Rapamycin, an mTOR inhibitor, has known immunomodulatory and anti-angiogenic properties.
• The impact of rapamycin on complex wound healing, involving multiple tissue layers, remains incompletely understood.

Purpose of the Study:

• To investigate the effects of rapamycin (RAPA) on the healing process of bladder and abdominal wall surgical wounds in a rat model.
• To evaluate the influence of RAPA on key cellular and molecular aspects of wound repair, including inflammation, angiogenesis, and fibroblast activity.

Main Methods:

• A randomized controlled trial was conducted on 14 male Sprague Dawley rats, divided into RAPA and placebo groups.
• Surgical procedures included midline laparotomy, bladder incision/closure, and layered closure of fascia and skin.
• Histological analysis assessed inflammatory cell infiltration, myofibroblast proliferation, microvessel density, and proliferation markers.

Main Results:

• Rapamycin treatment significantly reduced eosinophil, neutrophil, and myofibroblast presence in bladder, fascia, and dermis compared to controls.
• Mean microvessel density and VEGF expression were significantly lower in RAPA-treated wounds.
• Proliferating cell nuclear antigen (PCNA) indices were higher in the placebo group, indicating reduced cellular proliferation with RAPA.

Conclusions:

• Rapamycin treatment impairs multiple stages of wound healing, including inflammation, angiogenesis, and myofibroblast proliferation.
• The observed delay in wound healing due to RAPA is associated with a decrease in the tensile strength of the closures.
• These findings suggest that rapamycin may have detrimental effects on surgical wound repair, necessitating careful consideration in clinical applications.