Plasma cell-free DNA concentration increases during luteolysis in beef cows.

During cell death, DNA is fragmented and reaches the bloodstream in the form of cell-free DNA (cfDNA). Luteal cells must undergo an apoptotic process during structural luteolysis to begin a new estrous cycle. We hypothesized that cfDNA concentrations would increase when inducing luteolysis by applying prostaglandin F 2α (PGF2α) analog to the cycling cow. Multiparous non-pregnant and non-lactating Angus cows (Bos taurus; n = 15) were synchronized using the 7-day CoSynch + CIDR protocol. Ten days after estrus was detected, two treatments were applied (PGF2α, n = 10; or Con, n = 5). Twice a day, gray mode and color-Doppler ultrasonography were used to calculate area (CL-A) and luteal blood perfusion (LBP%). Additionally, we collected one blood sample for plasma progesterone (P4) and cfDNA concentrations for 4 consecutive days. Data analysis was performed using the GLM procedure of SAS. The luteolysis induction was demonstrated by a decrease in P4 concentrations (P ≤ 0.01) and CL-A (P ≤ .01) in the PGF2α group after 12 hours of the PGF2α injection. Reduction of LBP% (P ≤ 0.01) in the PGF2α group after 36 hours of the injection. The concentration of cfDNA showed a significant increase (P = 0.05) after 48 hours of the PGF2α application in the PGF2α group. In conclusion, cfDNA showed a significantly increased concentration after luteolysis induction, which can imply that cfDNA could be used as a luteolysis biomarker in plasma.