American Society of Hirudotherapy

Efficiency of medical leech on experimentally induced incisional wound healing in rats

Bilden A, Kara O, Kahraman M, Caglayan N, Cicek M (2025) · Journal of Complementary & Integrative Medicine · n=15

RCT evidence detailTrial reference
GRADE Very LowInsufficient evidence

Study Profile

Design
experimental preclinical animal study comparing wound healing across five groups: leech saliva topical, single leech therapy session, two leech therapy sessions, Phyto cream positive control, and untreated negative control; 15 rats with full-thickness dorsal incisional wounds randomly assigned in equal groups (Faculty of Medicine, Kirsehir Ahi Evran University, Turkiye)
Sample size (n)
15
Intervention
Five-arm comparison: (1) Leech Saliva (LS) topical application daily, (2) Leech Therapy-1 (LT-1) single session at day 0, (3) Leech Therapy-2 (LT-2) sessions at days 0 and 3, (4) Positive Control (PC) Phyto cream daily, (5) Negative Control (NC) no treatment
Comparator
Within-study comparison across the five experimental arms; positive and negative controls included
Primary endpoint
Wound healing assessed daily until complete closure, with terminal histological analysis (epithelial regeneration, granulation tissue thickness, inflammatory infiltrate, neovascularization)
Primary result
Both single-session and two-session leech therapy arms (LT-1, LT-2), as well as topical leech saliva (LS), showed accelerated wound healing compared to the untreated negative control; histological analysis confirmed positive wound healing effects of medicinal leech therapy; preclinical signal supporting therapeutic potential pending clinical translation
Follow-up duration
duration until complete wound healing in all arms (study-specific)
PMID
39891363

Key Findings

  • Five-arm preclinical comparison demonstrating accelerated wound healing with both whole leech and isolated leech saliva
  • Histological evidence of improved epithelial regeneration and granulation tissue formation in leech-treated arms
  • First Turkish preclinical study to compare single-session and two-session leech therapy in a rat wound model
  • Provides translational support for ongoing clinical research into leech therapy for chronic wounds and ulcers
  • Confirms that topical leech saliva alone (without whole-leech application) may have therapeutic potential

Limitations

  • Animal preclinical study only - no direct clinical translation
  • Small sample size (n=3 rats per arm) limits statistical power
  • Histological scoring may be subject to assessor bias
  • Single-strain, single-species rat model - generalizability to human wound healing untested
  • No molecular mechanism characterization reported (specific bioactive compounds responsible for healing not identified)

Clinical Implications

Bilden 2025 provides preclinical signal that both whole-leech therapy and topical leech saliva accelerate wound healing in a rat model. For US clinicians, the trial supports the broader translational hypothesis that leech-derived bioactives could be developed as a topical wound-healing therapy independent of the K040187 microsurgical device indication. The trial is hypothesis-generating only; substantial preclinical mechanism work and human RCTs would be needed before any clinical translation. The trial is included in the registry to document the active preclinical research program in this area.

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This website provides educational information and does not constitute medical advice, diagnosis, or treatment recommendations. Medicinal leech therapy carries clinically meaningful risks and should be performed only by qualified clinicians under institutionally approved protocols. FDA 510(k) clearance for medicinal leeches is limited to specific indications; investigational and off-label discussions are labeled accordingly. For patient-specific guidance, consult a qualified healthcare provider.