Temephos Decreases Sperm Quality and Fertilization Rate and Is Metabolized in Rat Reproductive Tissues at Low-Dose Exposure.

Temephos is an organophosphorus pesticide used in control campaigns against vectors that transmit diseases, including dengue, a public health concern. The WHO classifies temephos in category III and its safe concentration (low-observable-adverse-effect level) in male rats is 100 mg/kg/day for up to 44 days. Temephos inhibits acetylcholinesterase (AChE) and is metabolized in different tissues, probably by mixed-function oxidases; one of its metabolites is bisphenol S (BPS), which is considered an endocrine disruptor. The aim of this study was to evaluate the effects of temephos on sperm function and its biotransformation in the testis, epididymis, and other tissues to explore its toxicity in rats treated with 100 mg/kg/day/5 or 7 days (gavage). AChE activity was inhibited 70% starting on day 3 and 13 or 41% mortality was observed at 5 or 7 days, respectively. After 7 days, temephos significantly decreased sperm motility (30%) and viability (10%) and increased (10%) lipoperoxidation, and the sperm DNA exhibited no damage. Temephos was distributed and metabolized in all tissues, with the highest levels observed in the adipose tissue and temephos levels were 16-fold higher in the epididymis than in the testis. Notably, BPS was observed in the testis. At 5 days, decreased sperm motility (12.5%) and viability (5.7%) were observed and sperm fertilization decreased (30%). These results suggest that temephos decreases sperm quality and fertilization capacity at recommended safe concentrations and that it is metabolized in male reproductive tissues. This pesticide places the reproductive health of exposed people at risk, suggesting the need to reevaluate its toxicity.

Alterations in oocytes and early zygotes following oral exposure to di(2-ethylhexyl) phthalate in young adult female mice.

Because di(2-ethylhexyl) phthalate (DEHP) toxicity on ovarian function is incomplete, effects of DEHP oocyte fertilization and the resulting zygotes were investigated. Further, an analysis characterizing the stage of zygote arrest was performed. Female CD1 mice were dosed orally with DEHP (0, 20, 200 and 2000 µg/kg/day) for 30 days. Following an in vivo mating post-dosing, DEHP-treated females exhibited fewer oocytes/zygotes, fewer oocytes displaying the polar body extrusion, fewer 1-cell zygotes having 2-pronuclei, more unfertilized oocytes, and decreased number of zygotes at every stage of development. DEHP induced blastomere fragmentation in zygotes. DNA replication in zygotes directly assessed by the 5-Ethynyl-2'-deoxyuridine (5-EdU) incorporation assay and indirectly by dosing mice with 5-fluorouracil (5-FU) suggested that DEHP inhibits DNA replication. Our data suggest that DEHP at doses found in 'every-day' (200 µg/Kg/day) or occupational (2000 µg/Kg/day) environments induces zygote fragmentation and arrests its development from the 2-cell stage potentially impairing DNA replication.

Low concentrations of lead decrease the sperm fertilization ability by altering the acrosome reaction in mice.

Lead (Pb) exposure at high concentrations is associated with poor sperm quality, acrosome alterations, and low fertilization rate. Sperm capacitation and the acrosome reaction (AR) are required for successful fertilization. Actin polymerization is crucial for correct capacitation, and small GTPases, such as RhoA, Rac1, and Cdc42, are involved. This study aimed to evaluate the effects of Pb on sperm fertilization ability, capacitation, AR, and the mechanisms involved in mice exposed to low Pb concentrations. CD1 mice were exposed to 0.01% Pb2+ for 45 days through their drinking water and their spermatozoa were collected from the cauda epididymis-vas deferens to evaluate the following: AR (oAR: initial, sAR: spontaneous, and iAR: induced) using the PNA-FITC assay, sperm capacitation (P-Tyr levels), actin polymerization (phalloidin-TRITC), MDA production (stress oxidative marker), the RhoA, Rac1, and Cdc42 protein levels, and the in vitro fertilization (IVF). After the treatment, the blood Pb (PbB) concentration was 9.4 ±â€¯1.6 µg/dL. Abnormal sperm morphology and the oAR increased (8 and 19%, respectively), whereas the iAR decreased (15%) after a calcium ionophore challenge, and the actin polymerization decreased in the sperm heads (59%) and tails (42%). Rac1 was the only Rho protein to significantly decrease (33%). Spermatozoa from the Pb-treated mice showed a significant reduction in the fertilization rate (19%). Our data suggest that Pb exposure at environmental concentrations (PbB < 10 µg/dL) decreases the acrosome function and affects the sperm fertilization ability; this is probably a consequence of the low Rac1 levels, which did not allow adequate actin polymerization to occur.

Bisphenol A alters oocyte maturation by prematurely closing gap junctions in the cumulus cell-oocyte complex.

In ovarian follicles, cumulus cells communicate with the oocyte through gap junction intercellular communication (GJIC), to nurture the oocyte and control its meiosis arrest and division. Bisphenol A (BPA) is a monomer found in polycarbonate-made containers that can induce functional alterations, including impaired oocyte meiotic division and reduced molecule transfer in GJIC. However, how BPA alters oocyte meiotic division is unclear. We investigated whether BPA effects on oocyte meiotic division were correlated with reduced transfer in GJIC. Cumulus cell-oocyte complexes (COCs) isolated from mouse preovulatory follicles were cultured with 0, 0.22, 2.2, 22, 220, and 2200 nM BPA for 2 h. An additional 16-h incubation with epidermal growth factor (EGF) was performed to promote the occurrence of meiotic resumption and progression to metaphase II. Without EGF stimulus, BPA treatment increased the percentage of oocytes undergoing meiotic resumption, decreased GJIC in the COCs, and did not modify GJIC gene (Cx43 and Cx37) and protein (CX43) expression. Following EGF stimulus, BPA increased the percentage of oocytes that remained at the anaphase and telophase stages, and decreased the percentage of oocytes reaching the metaphase II stage. Concomitantly, BPA reduced the expansion of cumulus cells. Carbenoxolone (a GJIC inhibitor) and 6-diazo-5-oxo-l-norleucine (a cumulus cell-expansion inhibitor) exerted effects on meiotic division similar to those exerted by BPA. These data suggest that BPA accelerates meiotic progression, leading to impaired prophase I-to-metaphase II transition, and that this adverse effect is correlated with reduced bidirectional communication in the COC.

Estudio retrospectivo en el diagnóstico de Mycoplasma y Ureaplasma en muestra seminal de 89 pacientes en la Ciudad de México / Retrospective study on ureaplasma and mycoplasma detected in 89 patients semen

Resumen: Antecedentes: El Mycoplasma hominis, Mycoplasma genitalium y Ureaplasma urealyticum son microorganismos que se encuentran asociados a problemas reproductivos como la enfermedad pélvica inflamatoria en mujeres y la uretritis no gonocócica en hombres. Se han descrito alteraciones vinculadas a la infección por estos microorganismos, en parámetros reproductivos como la morfología espermática, el índice de infertilidad y la subfertilidad en el hombre. Objetivos: Determinar la incidencia de Mycoplasma spp. y Ureaplasma spp. en pacientes del Distrito Federal (México) y evaluar las posibles correlaciones con sus resultados en la espermatobioscopía. Material y método: Estudio retrospectivo de 89 pacientes positivos a Mycoplasma y Ureaplasma. Se analizaron los resultados de la espermatobioscopía y se correlacionaron estadísticamente. Resultados: Se obtuvo un aumento en el diagnóstico de estos 2 microorganismos en un 15% en el primer semestre del 2013 respecto al año 2012. Se encontraron diferencias significativas (P < 0.001) en la morfología espermática de pacientes positivos a alguno de los 2 agentes. Conclusiones: El Mycoplasma y el Ureaplasma se consideran como flora normal del tracto genitourinario, aun así, debe realizarse su diagnóstico en pacientes con historial de fertilidad y subfertilidad y debe ser considerado cuando en el espermograma informe de alteraciones morfológicas y aumento del recuento de leucocitos.

Abstract: Background: The Mycoplasma hominis, Mycoplasma genitalium and Ureaplasma urealyticum are microorganisms associated with reproductive problems such as pelvic inflammatory disease in women and non-gonococcal urethritis in men. Alterations have been described in reproductive parameters and sperm morphology, rate of infertility and subfertility in man. Objectives: The aim of this study was to determine the incidence of Mycoplasma spp. and Ureaplasma spp. in patients Federal District (Mexico) and to evaluate the possible correlations with the semen analysis results. Material and methods: Retrospective study of 89 patients positive for Mycoplasma and Ureaplasma, we analyzed the results of the semen analysis and correlated statistically. Results: We obtained an increase in the diagnosis of these two microorganisms, by 15% in the first half of 2013 compared with 2012. Significant differences (P <0.001) in sperm morphology in patients positive to one of the two agents, the most frequent was the Ureaplasma. Conclusions: Mycoplasma and Ureaplasma are considered normal flora of the genitourinary tract, even so, the diagnosis should be performed in patients with a history of fertility and subfertility and should be considered when reporting morphological abnormalities and increased leukocyte count.