Analysis of the role of prostaglandins in the fertilization process

This study was designed to elucidate the role of prostaglandins (PG) in the fertilization process, using indomethacin (ID), an inhibitor of PG biosynthesis, and mouse in vitro fertilization as a model for analysis. Spermatozoal viability, as assessed via motility, was not suppressed by ID at 100 and 150 micrograms/ml in 3-h incubation, but markedly by 200 micrograms/ml in 1-h incubation. On the other hand, ovum viability was not affected even by 200 micrograms/ml ID in 5-h incubation, as assessed via dye-excretion and morphology. Fertilization rates for 0, 100, 150 and 200 micrograms/ml ID were 58.8, 54.8, 24.3 and 18.9%, respectively; at 150 micrograms/ml and more, significant inhibition was noted. The reduction in spermatozoal viability at 200 micrograms/ml ID was not detected after supplementation of 50 micrograms/ml PGF2 alpha. Fertilization rates were 23.1 and 20.7% in the groups at 150 and 200 micrograms/ml ID with PG solvent, respectively. After supplementation of 50 micrograms/ml PGF2 alpha, the rates were 55.8% and 64.0%, respectively. The degenerated eggs significantly increased. The polyspermic eggs also tended to increase in the ID 200 micrograms/ml groups; however, after PGF2 alpha supplementation, the number of such eggs tended to decrease. Based on these facts, it is concluded that PG may play their role in fertilization not only via sperm, but also via eggs.