Platelet Rich Plasma: Pioneering a Paradigm Shift in Subclinical Endometritis Treatment

Repeat breeding syndrome associated with subclinical endometritis (SCE) remains a major cause of infertility in dairy cattle, as its subclinical nature often hampers timely diagnosis and therapeutic intervention, thereby limiting the success of conventional antimicrobial therapy. This study evaluated the therapeutic efficacy of intrauterine platelet-rich plasma (PRP) as an immunomodulatory, antibiotic-free alternative for the management of SCE in repeat breeder cows and aimed to standardize an effective intrauterine PRP dose regime.

Twenty-nine repeat-breeding cows diagnosed with SCE based on endometrial cytobrush cytology (>5% polymorphonuclear neutrophils, PMNs) were randomly allocated into three groups: untreated control, intrauterine cephapirin (500 mg), and intrauterine PRP (25 mL; ≥1×10⁶ platelets/µL). Changes in endometrial PMN percentage, bacterial load, pro-inflammatory cytokines (TNF-α and IFN-γ), interval to return to estrus, and conception rate were assessed.

Both PRP and antibiotic treatments significantly reduced endometrial PMN counts and inflammatory cytokine concentrations compared with untreated controls (p < 0.05). Intrauterine PRP markedly modulated the uterine inflammatory milieu, demonstrating substantial reductions in TNF-α and IFN-γ, even in animals with negative microbial cultures, highlighting its immune-regulatory action. PRP treatment also resulted in a significant decline in uterine bacterial load, likely mediated through enhanced intrinsic uterine defence mechanisms. Conception rates in PRP-treated cows (50%) were comparable to those achieved with antibiotic therapy and superior to untreated controls, with no adverse effects on estrus return interval.

Intrauterine PRP effectively restores uterine homeostasis and fertility in repeat breeder cows affected with SCE by concurrently attenuating inflammation, facilitating microbial clearance, and promoting endometrial regeneration.