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Equine veterinary journal2026; doi: 10.1002/evj.70342

Platelet-rich plasma exhibits antibacterial and anti-inflammatory effects in an in vitro donkey endometritis model.

Abstract: Infectious endometritis, mainly caused by Escherichia coli (E. coli) and Streptococcus equi subsp. zooepidemicus (SEZ), significantly impairs donkey reproductive performance. Platelet-rich plasma (PRP) shows promise as an anti-inflammatory and antibiotic alternative. Objective: To evaluate PRP's antimicrobial efficacy against key pathogens and assess its anti-inflammatory and tissue repair properties in an in vitro endometrial model. Methods: Non-randomised in vitro and explant experiments. Methods: In in vitro antibacterial assays, the inhibitory effects of PRP on the growth of E. coli and SEZ were evaluated. In an in vitro infected endometrial explant model, tissues were treated with PRP, ceftiofur (CEF), 1/2 MIC CEF, or PRP combined with 1/2 MIC CEF. Antibacterial efficacy was evaluated by bacterial load quantification, while inflammatory and healing responses were assessed by measuring the protein levels of pro-inflammatory cytokines (IL-1β, IL-6, TNF-α), anti-inflammatory cytokine (IL-10), tissue repair factor (TGF-β), matrix metallopeptidase 9 (MMP-9), and histological examination of the endometrium. Results: 50% PRP significantly inhibited E. coli and SEZ during an 8 h culture period (p < 0.05), although efficacy decreased by 24 h. In the SEZ model, PRP reduced bacterial load, IL-1β, IL-6, TNF-α, and TGF-β levels while enhancing the expression of IL-10 and MMP-9 (p < 0.05). In the E. coli model, PRP + 1/2 MIC CEF demonstrated synergistic antibacterial and optimal anti-inflammatory effects (p < 0.05). PRP also promoted epithelial and glandular repair as indicated by upregulated MMP-9 levels. Conclusions: Models may not fully replicate complex co-infections and cell interactions. Conclusions: The antibacterial efficacy of PRP depends on concentration, duration, and pathogen type, with PRP showing greater inhibitory effects against SEZ than E. coli. Application strategies should be tailored to the type of infectious endometritis to maximise the effect of PRP.
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Publication Date: 2026-10-04 PubMed ID: 42830113DOI: 10.1002/evj.70342Google Scholar: Lookup
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Summary

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Overview

  • This study investigated the antibacterial and anti-inflammatory effects of platelet-rich plasma (PRP) against bacterial pathogens causing infectious endometritis in donkeys, using in vitro models.
  • The research also assessed PRP’s ability to promote tissue repair in infected endometrial tissue, suggesting potential therapeutic use tailored to specific infections.

Background

  • Infectious endometritis is a uterine infection impacting donkey reproductive health, commonly caused by Escherichia coli (E. coli) and Streptococcus equi subsp. zooepidemicus (SEZ).
  • Traditional antibiotic treatments have limitations, prompting investigation into alternatives such as platelet-rich plasma (PRP), which is known for anti-inflammatory and healing properties.

Objectives

  • To evaluate the antimicrobial efficacy of PRP against E. coli and SEZ in vitro.
  • To assess PRP’s anti-inflammatory effects and ability to promote tissue repair in an in vitro donkey endometrial explant infection model.
  • To explore combination treatments using PRP and subinhibitory concentrations of the antibiotic ceftiofur (CEF) against these pathogens.

Methods

  • Antibacterial assays: In vitro experiments tested the inhibitory effects of various concentrations of PRP on bacterial growth over an 8 to 24-hour period.
  • Endometrial explant model: Donkey endometrial tissue samples were infected with E. coli or SEZ and treated with PRP alone, ceftiofur (full or half MIC), or a combination of PRP with half MIC ceftiofur.
  • Outcome measures:
    • Bacterial load quantification to measure antimicrobial efficacy.
    • Measurement of inflammatory markers — pro-inflammatory cytokines (IL-1β, IL-6, TNF-α), anti-inflammatory cytokine (IL-10), tissue repair factor (TGF-β), and matrix metallopeptidase 9 (MMP-9).
    • Histological examination of endometrial tissue to assess epithelial and glandular repair.

Results

  • Antibacterial effects:
    • 50% PRP concentration significantly inhibited growth of both E. coli and SEZ during initial 8-hour culture (p < 0.05), but effectiveness declined by 24 hours.
    • PRP showed greater antibacterial activity against SEZ compared to E. coli.
  • Anti-inflammatory and tissue repair effects in SEZ model:
    • PRP treatment lowered levels of pro-inflammatory cytokines IL-1β, IL-6, and TNF-α (p < 0.05).
    • There was a reduction in TGF-β, a tissue repair factor, suggesting modulation of the inflammatory phase.
    • Increase in anti-inflammatory cytokine IL-10 and MMP-9, indicating enhanced healing processes and tissue remodeling.
  • Effects in E. coli model:
    • Combination of PRP with half MIC of ceftiofur (PRP + 1/2 MIC CEF) showed a synergistic effect, achieving stronger antibacterial and anti-inflammatory results than either treatment alone (p < 0.05).
    • PRP promoted repair of epithelial and glandular tissue, supported by increased MMP-9 expression.

Conclusions and Implications

  • The antibacterial efficacy of PRP depends on concentration, exposure time, and pathogen type, with better inhibitory effects against SEZ than against E. coli.
  • Combination therapy of PRP with antibiotics like ceftiofur can enhance efficacy, especially against more resistant pathogens.
  • PRP also exerts beneficial anti-inflammatory effects and promotes tissue healing, which is critical in recovery from infectious endometritis.
  • Application strategies for PRP should be adapted based on the specific infectious agent to optimize therapeutic outcomes.
  • Limitations include the in vitro model’s inability to fully replicate complex in vivo conditions such as mixed infections and cellular interactions within the uterus.
  • These findings support further development of PRP-based therapies as potential alternatives or adjuncts to antibiotics for managing infectious endometritis in donkeys.

Cite This Article

APA
Ling Y, Lan X, Duan S, Yu J, Sun J, Qu H, Lu T, Wang Z, Zhu Y, Li J. (2026). Platelet-rich plasma exhibits antibacterial and anti-inflammatory effects in an in vitro donkey endometritis model. Equine Vet J. https://doi.org/10.1002/evj.70342

Publication

Equine veterinary journal
ISSN: 2042-3306
NlmUniqueID: 0173320
Country: United States
Language: English

Researcher Affiliations

Ling, Yun
  • Equine Clinical Diagnostic Center, College of Veterinary Medicine, China Agricultural University, Beijing, China.
Lan, Xin'er
  • Equine Clinical Diagnostic Center, College of Veterinary Medicine, China Agricultural University, Beijing, China.
Duan, Shiyu
  • Equine Clinical Diagnostic Center, College of Veterinary Medicine, China Agricultural University, Beijing, China.
Yu, Jie
  • National Engineering Research Center for Gelatin-Based Traditional Chinese Medicine, Shandong, China.
  • Dong-E E-Jiao Co. Ltd., Shandong, China.
Sun, Jinni
  • National Engineering Research Center for Gelatin-Based Traditional Chinese Medicine, Shandong, China.
  • Dong-E E-Jiao Co. Ltd., Shandong, China.
Qu, Honglei
  • National Engineering Research Center for Gelatin-Based Traditional Chinese Medicine, Shandong, China.
  • Dong-E E-Jiao Co. Ltd., Shandong, China.
Lu, Teng
  • National Engineering Research Center for Gelatin-Based Traditional Chinese Medicine, Shandong, China.
  • Dong-E E-Jiao Co. Ltd., Shandong, China.
Wang, Zixuan
  • Equine Clinical Diagnostic Center, College of Veterinary Medicine, China Agricultural University, Beijing, China.
  • State Key Laboratory of Veterinary Public Health and Safety, College of Veterinary Medicine, China Agricultural University, Beijing, China.
Zhu, Yiping
  • Equine Clinical Diagnostic Center, College of Veterinary Medicine, China Agricultural University, Beijing, China.
  • State Key Laboratory of Veterinary Public Health and Safety, College of Veterinary Medicine, China Agricultural University, Beijing, China.
Li, Jing
  • Equine Clinical Diagnostic Center, College of Veterinary Medicine, China Agricultural University, Beijing, China.
  • State Key Laboratory of Veterinary Public Health and Safety, College of Veterinary Medicine, China Agricultural University, Beijing, China.

Grant Funding

  • 2023YFD1302000 / National Key Research and Development Program of China

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