Correlation Between Intrafollicular IL-10, Progesterone, and Bovine Oocyte Developmental Competence

The developmental competence of oocytes is a critical limiting factor in bovine in vitro embryo production (IVEP). Our study aimed to investigate the relationship between the intrafollicular concentrations of interleukin-10 (IL-10) and progesterone (P4), follicle characteristics, and the subsequent developmental success of bovine oocytes. Follicular fluid (FF) and corresponding cumulus-oocyte complexes (n = 314) were collected from FSH-stimulated heifers. A novel, high-sensitivity Surface Plasmon Resonance Imaging biosensor was used to quantify IL-10, while P4 was measured by an enzyme-linked fluorescent assay. Oocytes were individually cultured to assess cleavage (Day 3) and blastocyst formation (Day 7). Statistical analysis revealed that intrafollicular IL-10 concentration was a significant positive predictor of developmental success, significantly correlating with blastocyst rate (ρ = 0.29, p = 0.016). Oocytes from follicles with IL-10 concentrations above an optimized cutoff of 142.16 pg/mL had a 16.33-fold greater chance of developing into a blastocyst (p = 0.006). A predictive model combining IL-10 and oocyte morphology demonstrated the highest accuracy for predicting blastocyst success (AUC = 0.724). Conversely, poor oocyte morphology (Grade 4) and large follicular volume (>1200 µL) were significantly associated with developmental failure. Intrafollicular P4 concentration was not directly correlated with embryo development but rather with follicle size. Our findings identify intrafollicular IL-10 as a potent biomarker for predicting bovine oocyte competence and suggest that its quantification using sensitive biosensor technology could enhance the efficiency of IVEP programs.