Effect of prostaglandins E 2 and F 2α on in vitro development and hatching of caprine blastocysts

Abstract

Prostaglandin E 2 has been shown to increase the ovine embryo hatching rate, and PGF 2α to reduce the development of rabbit, bovine, and rat embryos. The objective was to determine the effects of PGE 2 and PGF 2α on development of caprine embryos. Estrus was synchronized in does ( n = 25) with medroxyprogesterone acetate (MAP) intravaginal sponges for 12 days, and superovulated with 20 units of FSH. On day 6 following estrus, embryos were flushed ( n = 128) and incubated individually per well in 25 μl droplets of TCM-199 and BSA (8 mg/ml) for 6 days at 38.5 °C in a 5% CO 2: air with one of the following treatments: (1) control (0.0002% EtOH), (2) PGE 2 (7 ng/ml), (3) PGF 2α (7 ng/ml), (4) low PGE 2:high PGF 2α (3.5 ng/ml:14 ng/ml), (5) balanced PGE 2:PGF 2α (7 ng/ml:7 ng/ml), or (6) high PGE 2:low PGF 2α (14 ng/ml:3.5 ng/ml). Treatment with PGE 2 alone reduced ( P < 0.05) the hatching rate (1/15; 7%). The hatching rate of embryos treated with PGF 2α alone (9/18; 50%), low PGE 2:high PGF 2α (8/16; 50%), and balanced PGE 2:PGF 2α (11/16; 69%) were similar to control (6/18; 33%). In contrast, the hatching rate was non-significantly increased (13/18; 72%) with the high PGE 2:low PGF 2α treatment. None of the treatments affected development from the morula to blastocyst stage. From the current data, it can be concluded that PGE 2 alone reduced hatching rate, and PGF 2α alone had no effect on the development of caprine embryos. High concentrations of PGE 2 with PGF 2α improved the hatching rates. Thus, uterine concentrations of PGE 2 may need to reach a threshold level to improve embryo hatching, as previously reported, while increased uterine concentrations of PGF 2α during early pregnancy would not affect development of the embryo.