Effects of seminal plasma on uterine polymorphonuclear dynamics and fertility of jennies inseminated with glycerol-free, frozen-thawed donkey semen

Background

Insemination of jennies with frozen-thawed donkey semen usually causes an intense uterine inflammation and results in low fertility.

Objectives

To evaluate the effects of seminal plasma on the time course of endometrial inflammation after insemination of jennies with donkey semen that was frozen using formamides as cryoprotective agents.

Methods

Jennies were inseminated with fresh semen (FS, n = 14), frozen-thawed semen (FTS, n = 12) or frozen-thawed semen plus seminal plasma (FTS-SP, n = 13), and uterine cytology was evaluated at 8, 24 and 48 h post-insemination.

Results

At 8 h post-insemination the percentage of polymorphonuclear cells (%PMN) was higher (P < 0.05) in the FTS group (90.7 ± 4.6) than in the FS group (68.9 ± 4.3), while jennies in the FTS-SP had intermediate levels (82.7 ± 4.5). At 24 h the %PMN was higher (P < 0.05) in jennies in the FTS-SP group (84.8 ± 4.5) than in the other groups. However, a faster decline in %PMN from 24 h to 48 h post-insemination in the FTS-SP group resulted in no difference between groups at 48 h. All groups still had mean %PMNs above 50 % at 48 h post-insemination, but the females that became pregnant had faster clearance rates from 24 h to 48 h post-insemination, resulting in lower %PMNs (44.4 ± 3.8) than those in the non-pregnant jennies (64.8 ± 3.6) at 48 h post-insemination (P < 0.05).

Conclusion

Seminal plasma induced faster uterine polymorphonuclear clearance after 24 h post-insemination in jennies inseminated with frozen-thawed donkey semen, and this effect could be related to improved fertility.