[Influence of Ureaplasma Urealyticum Infection on Testicular Tissue Structure and Secretion Function in Rats].

OBJECTIVE: To study the influences of ureaplasma urealitycum (UU) infection on testicular tissue structure and secretion function in rats. METHODS: Forty clean grade male SD rats were randomly divided into the experiment group A (at 7 d after surgery), experiment group B (at 14 d after surgery), control group C (at 7 d after surgery) and control group D (at 14 d after surgery). There were 10 rats in each group. The experimental groups were injected with 0.6 mL UU4 through bladder. In the same way, the control groups were injected with the same volume of UU liquid medium. At day 7 and 14 after injection, the structures of testis of all rats were observed by light microscopy and spermatogenic cells by transmission electron microscopy. The content of testosterone in plasma and testicular fluid were detected by chemiluminescence method. RESULTS: The changes of inflammatory pathology (including the layer and amount of spermatogenic cell decreasing, inflammatory cell infiltrating and mature sperms decreasing) in the testis of group A and group B were found by light microscopy, and the inflammatory changes in group B were lighter than those in group A. The structures of testicular tissue in group C and group D were normal. The apoptosis performances of germ cell (including the cell membrane corrugated, nuclear chromatin concentration and nuclear rupture) in the testis of group A and group B were found by transmission electron microscopy, and the changes in group B were lighter than those in group A. The structures of germ cell in group C and group D were normal. The levels of plasma testosterone in group A and group B were significantly lower than that in group C and group D (P<0.01), the difference between group A and group B was not statistically significant. The testosterone level in testis interstitial fluid in group A was significantly lower than that in other groups (P<0.01), the differences between other groups were not statistical significant. CONCLUSIONS: The testicular tissue of UU infected rats can have various pathological damage and functional changes, further confirming that UU infection can cause male infertility. The pathological damage and functional changes of the testicular tissue of rats after UU infection can be gradually restored with the extension of the duration of the disease.

Staphylococcal enterotoxin B and α­toxin induce the apoptosis of ECV304 cells via similar mechanisms.

Staphylococcal enterotoxin B (SEB) and α­toxin produced by Staphylococcus aureus (S. aureus) are important in the pathogenesis of diseases. In the present study, we investigated the effects of SEB and α­toxin on ECV304 cells. It was identified that both SEB and α­toxin were capable of inducing the apoptosis of ECV304 cells in a dose­ and time­dependent manner. In addition, SEB and α­toxin were able to induce the expression of TNF­α and the activation of caspase­3 and ­8 in the ECV304 cells. The inhibition of TNF­α (with its neutralizing antibody) and caspase­3 and ­8 [with the corresponding inhibitory peptides; z-N-acetyl-Asp-Glu-Val-Asp-aminomethyl-coumarin (DEVD)-fluoromethyl ketone (FMK) for inhibition of caspase­3 and z-N-acetyl-Ile-Glu-Thr-Asp (IETD)-FMK) for inhibition of caspase­8] significantly decreased the rates of cell apoptosis induced by SEB and α­toxin, but was not able to completely block the induced cell apoptosis. These data suggest that SEB and α­toxin induce ECV304 cell apoptosis via a similar mechanism, which is partially mediated by the extrinsic death pathway involving TNF­α and caspase­8. These results provide insights into the synergistic pathogenicity of SEB and α­toxin during S. aureus infection.

Role of α-toxin-induced apoptosis of umbilical vein endothelial cells in vertical infection of Staphylococcus aureus L-form.

OBJECTIVE: To investigate α-toxin-induced apoptosis of umbilical vein endothelial cells and explore its role in vertical infection of Staphylococcus aureus L-form. METHODS: HUV-EC-C cells exposed to different concentrations (0, 10, 30, 90, and 270 ng/ml) of α-toxin for different time lengths (0, 2, 4, 6, and 8 h) were examined for apoptosis using flow cytometry with Annexin V-PI staining. The levels of tumor necrosis factor-α (TNF-α) and the activities of, caspase-3 and caspase-8 in the cell culture were detected by ELISA and colorimetric method, respectively. α-Toxin-induced cell apoptosis was also analyzed in HUV-EC-C cells treated with a neutralizing antibody of TNF-α or with the inhibitory peptides of caspase-3 (zDEVD-FMK) and caspase-8 (zIETD-fmk). RESULTS: α-Toxin induced apoptosis of HUV-EC-C cells in a dose- and time-dependent manner and caused significantly enhanced expression of TNF-α and the activation of both caspase-3 and caspase-8. Inhibition of TNF-α with its neutralizing antibody and the inhibitory peptides of caspase-3 or -8 all significantly decreased α-toxin-induced cell apoptosis, and the caspase-3 inhibitor completely blocked α-toxin-induced cell apoptosis. CONCLUSION: α-Toxin-induced apoptosis is partially mediated by the extrinsic cell death pathway of TNF-α and caspase-8 and plays an important role in the vertical infection of S. aureus L-form to affect fetal growth and development.

Teratogenicity of Staphylococcus aureus L-forms using a mouse whole-embryo culture model.

Our previous studies have suggested that Staphylococcus aureus L-forms are able to pass through the placental barrier of mice from the maternal side to the fetal body and affect fetal growth and development, but little is known about the direct influence of S. aureus L-forms on embryos during the critical period of organogenesis. Mouse embryos at gestational day 8.5 were cultured in vitro for 48 h with 0, 50, 100, 200 or 400 c.f.u. S. aureus L-forms ml(-1). At the end of the culture period, the mouse embryos were assessed morphologically for viability, growth and development. Bacteriological and immunohistochemical staining were used to determine the existence of S. aureus L-forms in embryonic tissues. We found that both crown-rump length and head length of mouse embryos exposed to S. aureus L-forms at a concentration of 50 c.f.u. ml(-1) were reduced. When the mouse embryos were exposed to 100, 200 or 400 c.f.u. S. aureus L-forms ml(-1), the total morphological score, number of somites, dry embryo weight, yolk sac diameter, crown-rump length and head length were significantly lower than those of the control group. With the increased concentration of S. aureus L-forms in the culture medium, there were fewer normally developed embryos and more embryos with abnormalities or retardation in growth. S. aureus L-forms detected by Gram-staining and immunohistochemical detection of antigen were found in the tissues of embryos infected by S. aureus L-forms. These data suggest that S. aureus L-forms exert a direct teratogenic effect on cultured mouse embryos in vitro.

[Effect of maternal staphylococcal enterotoxin B administration during pregnancy on CD3⁺ TCR Vß8⁺T cells of adult offspring rats].

OBJECTIVE: To investigate the influence of maternal staphylococcal enterotoxin B (SEB) administration during pregnancy on CD3⁺ TCR Vß8⁺T cells of adult offspring rats. METHODS: Pregnant maternal rats at gestational day (GD) 16 were injected intravenously with 15 µg SEB in 0.2 ml PBS (SEB group), and the control rats receive the same volume of PBS. Flow cytometry was used to determine the levels of CD3⁺ TCR Vß8⁺T cells in both the thymus and peripheral blood of adult offspring rats and the response of these cells to a secondary SEB administration. RESULTS: Maternal SEB administration during pregnancy significantly decreased the percentages of CD3⁺TCR Vß8⁺T cells in the thymus in adult female (1.760-2.714) and male (1.098-2.088) offspring rats (P<0.05). The change of CD3⁺TCR Vß8⁺T cells in the peripheral blood was similar to that in the thymus. In the control adult offspring rats, SEB administration at adulthood significantly reduced the percentages of CD3⁺TCR Vß8⁺T cells in both the thymus and peripheral blood (P<0.05). But in SEB group, a secondary SEB administration in adult offspring rats significantly increased the percentage of CD3⁺TCR Vß8⁺T cells in the peripheral blood (P<0.05) but not in the thymus (P>0.05). CONCLUSION: Maternal SEB administration during pregnancy can change the response of CD3⁺ TCR Vß8⁺T cells of adult offspring rats to a secondary SEB administration.