Role of Inflammatory Cytokines in Embryonic Implantation Failure and Recurrent Pregnancy Loss in Dairy Cattle: Development of an Immune Risk Index for Pregnancy Outcome Prediction
DOI:
https://doi.org/10.48165/ijar.2025.46.04.23Keywords:
Dairy cattle, inflammatory cytokines, implantation failure, recurrent pregnancy loss, Th1/Th2 balance, pre dictive modellingAbstract
Background: Embryonic implantation failure and recurrent pregnancy loss (RPL) represent major causes of reproduc tive inefficiency in dairy cattle, resulting in substantial economic losses. While immune dysregulation has been impli cated, comprehensive profiling of inflammatory cytokines and their predictive value for pregnancy outcomes remains limited. Objective: This study aimed to characterize the inflammatory cytokine profile in cows with implantation failure and RPL, establish diagnostic cut-off values, and develop an Immune Risk Index (IRI) for predicting pregnancy out comes. Methods: One hundred eighty multiparous Holstein-Friesian cows were allocated to four groups based on repro ductive history and current breeding cycle outcomes: Normal Fertility (NF, n=45), Single Embryonic Loss (SEL, n=45), Recurrent Pregnancy Loss (RPL, n=45), and Implantation Failure (IF, n=45). Blood samples were collected on Days 0, 7, 14, 21, and 35 post-AI for analysis of pro-inflammatory cytokines (IL-1β, IL-6, IL-8, IL-17, TNF-α, IFN-γ), anti-inflam matory cytokines (IL-4, IL-10, TGF-β), acute phase proteins (Hp, SAA, CRP), progesterone (P₄), and pregnancy-associ ated glycoproteins (PAGs). Th1/Th2 ratio was calculated. ROC analysis and logistic regression were performed. Results: Cows with IF and RPL exhibited markedly elevated (P < 0.05) pro-inflammatory cytokines: IL-6 (42.8 → 128.5 pg/mL), TNF-α (18.4 → 56.8 pg/mL), IFN-γ (24.6 → 72.4 pg/mL), with concurrent suppression of IL-10 (86.4 → 32.6 pg/mL) and elevated Th1/Th2 ratio (0.42 → 2.86). ROC analysis revealed IL-6/IL-10 ratio as the strongest predictor of pregnancy failure (AUC = 0.94) with optimal cut-off of 2.8 (sensitivity = 92.4%, specificity = 88.6%). The proposed Immune Risk Index achieved 93.2% accuracy for pregnancy outcome prediction. Conclusion: This study establishes a comprehensive inflammatory cytokine signature associated with implantation failure and RPL, providing validated biomarkers and a practical IRI for early identification of at-risk pregnancies in dairy cattle.References
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