Secretion of stem cell factor and granulocyte-macrophage colony-stimulating factor by mouse embryos in culture: influence of group culture.

Previous studies showed that the addition of a growth factor to the culture medium could modulate embryo development. The possible secretion of different factors to the culture medium by the embryo itself, however, has been poorly evaluated. The present study was designed to investigate: (1) the influence of single or group culture on the development of 2-cell mouse embryos (strain CD-1) to the blastocyst stage; (2) the release of granulocyte-macrophage colony-stimulating factor (GM-CSF) and stem cell factor (SCF) into the culture medium by the embryo; and (3) the levels of GM-CSF and SCF in the culture medium from both single and group embryos. Two-cell CD-1 mouse embryos were cultured for 96 h singly or in groups of five embryos per drop. GM-CSF and SCF were assayed by ELISA in the complete culture medium. It was found that embryos cultured in groups gave a higher percentage of total blastocyst formation and hatched blastocyst when compared with single embryo culture. The mouse embryos secreted GM-CSF and SCF to the culture medium. The concentration of these cytokines is significantly higher in the group cultures than the level found in single cultures. In conclusion, mouse embryos in culture secrete GM-CSF and SCF to the culture medium and the concentration of these cytokines increases during communal culture. These factors may be operating in both autocrine and paracrine pathways to modulate embryo development during in vitro culture.

Evidence favoring sperm selection over sperm competition in the interaction between human seminal plasma and sperm motility in vitro.

The effect on sperm motility of sperm-sperm and sperm-seminal plasma interactions was studied among homologous and heterologous sperm. There were no significant interactions between sperm in vitro, but it was found that seminal plasmas of different donors have different effects on sperm motility, and different sperm react differently to the same seminal plasma. Sperm showed higher motility in a pure physiological solution than when mixed with seminal plasma, even if the plasma and sperm came from the same donor. Various plasma components are responsible for this modulation of sperm motility. It would appear that large numbers of sperm are adaptive, among other things, because they are involved in sperm selection.

Chlamydia trachomatis and sperm lipid peroxidation in infertile men.

AIM: To relate the presence of anti-Chlamydial trachomatis IgA in semen with sperm lipid membrane peroxidation and changes in seminal parameters. METHODS: Semen samples of the male partners of 52 couples assessed for undiagnosed infertility were examined for the presence of IgA antibody against C. trachomatis. The level of sperm membrane lipid peroxidation was estimated by determining the malondialdehyde (MDA) formation. RESULTS: Sperm membrane of infertile males with positive IgA antibodies against C. trachomatis showed a higher level of lipid peroxidation than that of infertile males with negative IgA antibody (P<0.05). There was a positive correlation (P<0.01) between the level of C. trachomatis antibody and the magnitude of sperm membrane lipid peroxidation. All the other tested semen parameters were found to be similar in the two groups. CONCLUSION: The activation of immune system by C. trachomatis may promote lipid peroxidation of the sperm membrane. This could be the way by which C. trachomatis affects fertility.

Relation between immunosuppressive PGE(2) and IL-10 to pro-inflammatory IL-6 in seminal plasma of infertile and fertile men.

In vitro studies have reported that seminal plasma of fertile men has more inhibitory mitogenic effect and higher suppressive activity on antibody-dependent cellular cytotoxicity than seminal plasma from infertile males. Is it possible that variations in the seminal plasma composition could explain these results? The present study was conducted to investigate the relation between immunosuppressive PGE(2) and IL-10 to pro-inflammatory IL-6 in seminal plasma of infertile and fertile men. Utilizing specific ELISA commercial kit, semen samples from 45 infertile undiagnosed and 25 fertile men were examined for the presence of PGE(2), IL-10, and IL-6. The IL-6 concentration in seminal plasma of infertile men was significantly higher than that of fertile men (p<.0 4). However, levels of IL-10 were lower for the semen of infertile men than that of fertile men (p<.04). No differences were observed in PGE(2) concentrations between both groups. Increase in pro-inflammatory cytokines, such as IL-6, and decrease in immunosuppressive ones, such as IL-10, could alter the tolerance to sperm cell in male and female tracts and reduce the favorable conditions to reach the fecundation and implantation. It is necessary to conduct further studies that include other pro- and anti-inflammatory substances to evaluate the importance of the immune balance of semen in human fertility.

Bioactivity of serum hCG in preeclampsia.

OBJECTIVE: To compare hCG levels, obtained by biologic and immunologic means, in women with normal pregnancies and women with preeclampsia. METHODS: Peripheral blood samples from women in the third trimester with preeclampsia (n = 30) or normal pregnancies (n = 30) were assayed for immunoactive and bioactive hCG (mouse Leydig cell testosterone production assay). RESULTS: Serum bioactive hCG levels tended to be lower than normal, and immunoactive hCG levels tended to be higher in women with preeclampsia, but the differences were not statistically significant. However, the ratio of bioactive to immunoactive hCG was significantly lower than normal for preeclamptic women (0.70 +/- 0.28 vs. 1.15 +/- 0.35 for normotensive pregnant women [mean +/- standard deviation], P <.001). CONCLUSION: The ratio of bioactive to immunoreactive serum hCG is lower among preeclamptic than among normotensive pregnant women.

Interleukin-6 (IL-6) in seminal plasma of infertile men, and lipid peroxidation of their sperm.

Concentrations of tumor necrosis factor-alpha (TNF-alpha) and interleukin-6 (IL-6) in seminal fluid, as well as levels of sperm lipid membrane peroxidation, were investigated in fertile and infertile men. Semen samples, obtained by masturbation from 37 infertile and 14 fertile men, were examined for the presence of TNF-alpha and IL-6. The level of lipid peroxidation of the sperm membrane was measured by determining malondialdehyde (MDA) formation. The correlation between the IL-6 and the TNF-alpha concentrations in seminal plasma with the levels of lipid peroxidation of the sperm membranes was statistically evaluated. The IL-6 concentration in seminal plasma of infertile men was significantly higher than that of fertile men (p < .05). Similarly, the level of membrane lipid peroxidation was higher for the semen of infertile men than that of fertile men (p < .001). A significant positive correlation was found between IL-6 levels in seminal plasma and membrane sperm lipid peroxidation (p < .002), but not between this parameter and TNF-alpha levels in seminal plasma. These findings suggest a possible association between IL-6 seminal plasma levels and lipid peroxidation of sperm membrane. Stimulation of reactive species production by human sperm and leucocytes, induced by the high levels of IL-6, could explain these results.