90 Effects of treatment with the nonsteroidal anti-inflammatory drug Anafen prior to embryo recovery and the number of embryo flush procedures performed on prostaglandin levels in uterine fluid and pregnancy rate following embryo transfer

Some studies have shown that performing a second flush during embryo collection can increase the number of embryos recovered. However, this technique results in greater uterine manipulation that may increase PGF2α in the uterine fluid of donor cows and affect pregnancy rate in recipient females. Two experiments were conducted (1) to determine whether PGF2α concentration in uterine fluid was affected by treatment with a non-steroidal anti-inflammatory drug (NSAID) before embryo recovery and (2) to determine whether the percent of recipients becoming pregnant following embryo transfer (P/ET) was affected by flush number. In both experiments, lactating Holstein cows were used as donors (n = 18 and 34, respectively) and subjected to a standard superovulation protocol (Baracaldo et al. 2000 Theriogenology 53, 1239-1250, DOI: 10.1016/S0093-691X(00)00268-5). Embryo recovery was performed using 2 catheters that were inserted simultaneously into the uterus, 1 into each horn. During the first flush, a volume of 300 mL of flush medium was used in each horn. At the end of the first flush approximately 75 mL of fluid was left and, after 1 h, a second flush was performed to recover the remaining fluid. Samples were taken from each horn at the first and second flush to determine PGF2α concentration using a bovine PGFM ELISA kit. Data for PGF2α concentrations in uterine fluid were presented as the average of both uterine horns. In Exp. 1, donors were randomly assigned to be treated with or without 1.2 g of the NSAID Anafen (ketoprofen) IM 20 min before embryo recovery. In Exp. 2, recovered grade-1 embryos from the first and second flush procedures were frozen in ethylene glycol and subsequently transferred to synchronized Holstein heifers (n = 106 and 49 for the first and second flushes, respectively). Pregnancy was diagnosed by rectal palpation at Day 60. All data were analysed using t-test. In Exp. 1, Anafen treatment 20 min before embryo recovery reduced PGF2α in uterine fluid during the second flush procedure (105.9 ± 11.4 v. 43.6 ± 5.7 pg/mL; P < 0.001), but not during the first (54.7 ± 7.3 v. 44.2 ± 5.6 pg/mL; P = 0.34). In Exp. 2, PGF2α in uterine fluid was greater for the second flush as compared to the first flush (95.9 ± 7.4 v. 56.3 ± 5.5 pg/mL; P < 0.001). A total of 345 viable embryos were recovered from the 34 donors in Exp. 2 (n = 276 and 69 for the first and second flushes, respectively). The P/ET at Day 60 was greater (P < 0.05) for recipients that received embryos from the first flush as compared to recipients that received embryos from the second flush (64.2 v. 49.0%). Taken together, the results of the present study indicate that the second flush procedure results in greater PGF2α levels in uterine fluid and that embryos recovered during the second flush are less likely to establish pregnancy following transfer. Moreover, pretreatment of donors with the NSAID Anafen reduced PGF2α levels in uterine fluid during the second flush. Further research is needed to determine whether treatment of donors with NSAID can improve the P/ET achieved following the transfer of embryos recovered following a second flush procedure.