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The influence of estrogens on mouse sperm capacitation and acrosome reaction in vitro.
Tejnická, Magda ; Komrsková, Kateřina (advisor) ; Maňásková, Pavla (referee)
- 7 - Abstract There are an increasing amount of compounds in the environment that can have a negative effect on reproductive parameters in both male and female organism. There has been a worldwide decline of sperm quality during past decades and this fact lead to an increase of unnatural ways of conception through assisted reproduction techniques in the specialised centres. Natural estrogens are one of these compounds and they get into waste water after being excluded from the body by the urine. They get back into the human body from drinking water or from the food, and they can interfere with function of endogenous hormones in very low concentrations. For these reasons it is up to date to deal with the influence of these compounds on mammalian sperm. For many years, estrogens have been considered typically female sex hormones. It is now certain that they are also very important in the regulation of male reproduction. Endogenous estrogens in mammalian males are an important part of the endocrine system. Estrogens play an important role in the development of germ cells, spermatogenesis and processes leading to successful egg fertilization such as a capacitation or acrosomal reaction. Tyrosine phosphorylation is one of the essential steps for the properly ongoing process of capacitation in sperm followed by...
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Functional analysis of sperm quality after endocrine disruptor treatment
Linhartová, Zuzana ; Liberda, Jiří (advisor) ; Ryšlavá, Helena (referee)
The aim The aim of my study was to determine whether the selected endocrine disruptors (EDs) affect reproductive parameters of sperm. Due to two experimental models, in which was tested the influence of selected Eds, my work is divided into two parts: A) On the boar model (Sus scrofa) was tested effect of selected EDs (zearalenone (ZEN), di(2-ethylhexyl) phthalate (DEHP), vinclozolin (VIN) on the course of capacitation, acrosome responses in vitro and changes in the detection and localization of selected proteins. B) On the fish model (Perca fluviatilis L.) was tested the influence of the selected ED- bisphenol A (BPA) on the motility and velocity of fish sperm movement. Results Mammalian model In mammalian model the course of capacitation and acrosome reaction was significantly influencing by the examined EDs in comparision with control samples. The increase of the number of marked cells during capacitation and reduce of the number of marked cells after AR compared with the differences between experimental and control samples was confirmed by the flow cytometry method. At higher concentrations EDs clearly inhibited acrosome response and thus reduce the number of sperm capable of fertilization. The relevancy of the results of detection acrosome reaction was confirmed by using various methodological...
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Interaction of sperm surface proteins in the reproduction process
Jonáková, Věra ; Kraus, Marek ; Maňásková, Pavla ; Liberda, J. ; Tichá, M.
Mammalian fertilization includes highly regulated biochemical interactions between complementary molecules located on the surfaces of both gametes as well as those present in the natural environment of the gametes. Boar seminal plasma proteins AQN, AWN spermadhesins and DQH protein that are bound to the sperm at ejaculation play important role in the reproduction process. Binding of sperm to epithelial cells, recognition of gametes and binding of sperm to glycoprotein of zona pellucida are mediated by protein-saccharide interaction, lektin-type interaction. Another type of interaction (protein-protein) participates in the formation of aggregated forms, which seem to be the natural functional forms of seminal plasma proteins. Protein aggregates form the sperm coating layers and their re-modeling in the female reproductive tract is imporatnt for the sperm capacitation and for the primary binding of spermto the ovum.
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Dynamics of acrosome reaction during intra-specific sperm competition in rodents.
Veselá, Kateřina ; Hortová, Kateřina (advisor) ; Pěknicová, Jana (referee)
Dynamics of acrosome reaction during intra-specific sperm competition in rodents Sperm acrosome integrity is disturbed in promiscuous species field mice (Apodemus) and more than half of the spermatozoa undergoing spontaneous acrosome reaction (AR) before binding to the zona pellucida. In Muridae it is documented a generally high rate of spontaneous AR, and the percentage increases in promiscuous species up to 60 % in 60 min capacitation in vitro. The acrosome integrity positively corellates with presence of CD46 protein which absence in wood mouse is fenotypicaly same as in CD46 knock-out mouse leading to accelerated spontaneous AR. It is necessary to clarify whether for mouse sperm it is essential the primary binding of intact sperm to zona pellucida of the egg or whether it is preferred secondary sperm binding after spontaneous AR. In this context, the question is whether there is a relocalization of the key fusion protein IZUMO in sperm during spontaneous AR. IZUMO relocalization was monitored by immunofluorescence at specific times of capacitation in vitro during spontaneous and induced AR. IZUMO relocalization as closely connected to actin cytoskeleton, and β1 integrins. Dynamics and localization of β1 integrin during spontaneous and induced AR was also detected by immunofluorescence. Our results...
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Detection of mannosidase in the porcine urogenital tract – study of the sperm releasing from oviductal reservoir
Maňásková, Pavla ; Ren, Š. ; Jelínková, Jitka ; Krejčová, T. ; Liberda, J.
One of the most important steps of reproduction process is the meeting of sperm with oocyte. Binding of sperm with oviductal cells maintains spermatozoa in fertile state. The beginning of sperm capacitation is associated with oocyte ovulation resulting in the sperm release from oviductal reservoir. Hormonal changes after ovulation probably induce distinct oviductal secretion leading to disruption of the sperm protein binding with oviductal saccharide moieties. Another eventuality of the sperm releasing from oviductal reservoir is a change of oviductal environment caused by components of follicular fluid transported with oocyte after ovulation. In the pig, previous studies indicate lectin-type interaction of sperm protein receptors by mannose structures on the surface of oviductal cells. Our study was focused on enzymatic activity of mannosidase and its detection in porcine oviduct (fluid and tissue) and follicular fluid during hormonal cycle. In fluid from follicles in early and late hormonal stages, we measured mannosidase activity by colorimetric methods at physiological and acidic pH. Expression of secreted mannosidase was studied by specific antibody in follicular and oviductal fluids, and oviductal tissues during hormonal cycle. Clearly increased enzymatic activity of secreted mannosidase was found as specific-species in porcine fluid from follicles in late stage of hormonal cycle. On the other hand, detection of secreted mannosidase in follicular fluid as well as in oviductal fluid did not shown any significant differences during hormonal cycle. In oviductal isthmic tissue, we detected decreased protein expression of secreted mannosidase at middle and late follicular phases. These results suggest possible role of follicular mannosidase rather than oviductal one in the sperm releasing from oviductal reservoir in the pig. The additional study of the gene expression of secreted form of mannosidase in oviductal tissue during hormonal cycle should be necessary.
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