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Influence of polymorphonuclear granulocytes on the zona-free hamster oocyte assay
F R Vogelpoel1, R J van Kooij, E R te Velde
1Department of Clinical Bacteriology, Academic Hospital, Utrecht, The Netherlands.
Abstract:
To gain more insight into a possible detrimental influence of polymorphonuclear granulocytes (PMN) on fertility, PMN were added to spermatozoa and oocytes in the hamster oocyte assay. Addition of 2.5 x 10(6)/ml PMN to the sperm suspension at the start of the first incubation period (capacitation period) resulted in a significant decrease (P less than 0.03) in the number of decondensed sperm-heads per hamster oocyte (the decondensation index). When a concentration of 0.5 x 10(6)/ml PMN was used, no decrease was found. Stimulation of PMN by phorbol myristate acetate (PMA) did not enhance the inhibitory action of PMN. After incubation of oocytes with PMN for 1 h, an almost total inhibition of decondensation was observed. A significant inhibition could also be obtained when unstimulated PMN (2.5 x 10(6] were added at the start often 3 h coincubation period of spermatozoa and oocytes (P less than 0.004). The inhibition by PMN decreased to a nonsignificant level when the hydroxyl radical scavenger thiourea was present. The possible mechanisms by which PMN affect the results of the hamster oocyte assay and the possible implications of the presence of PMN in the genital tract are discussed.
Insights
Polymorphonuclear granulocytes (PMN) can negatively impact fertility by inhibiting sperm decondensation in hamster oocyte assays. Higher PMN concentrations significantly reduced sperm function, suggesting a role in reproductive health.
Area of Science:
- Reproductive Biology
- Immunology
- Cell Biology
Background:
- Polymorphonuclear granulocytes (PMN) are immune cells that may influence fertility.
- The specific impact of PMN on sperm-oocyte interactions requires further investigation.
- The hamster oocyte assay is a model system for evaluating sperm function.
Purpose of the Study:
- To investigate the potential detrimental effects of PMN on fertility using the hamster oocyte assay.
- To determine the concentration-dependent effects of PMN on sperm decondensation.
- To explore the mechanisms underlying PMN-mediated inhibition of sperm function.
Main Methods:
- Polymorphonuclear granulocytes (PMN) were added to spermatozoa and oocytes in the hamster oocyte assay.
- Varying concentrations of PMN (2.5 x 10^6/ml and 0.5 x 10^6/ml) were tested.
- The effect of phorbol myristate acetate (PMA) stimulated PMN and the hydroxyl radical scavenger thiourea were evaluated.
Main Results:
- A significant decrease in the decondensation index was observed with 2.5 x 10^6/ml PMN (P < 0.03).
- No significant inhibition was found at a PMN concentration of 0.5 x 10^6/ml.
- PMN incubation with oocytes for 1 hour caused near-total inhibition of decondensation; thiourea reduced this inhibition.
Conclusions:
- High concentrations of PMN can significantly inhibit sperm decondensation in the hamster oocyte assay.
- PMN may exert inhibitory effects through mechanisms involving reactive oxygen species.
- The presence of PMN in the genital tract could potentially impact fertility.