scholarly journals The Modulation of Functional Status of Bovine Spermatozoa by Progesterone

Animals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1788
Author(s):  
Vitaly Denisenko ◽  
Irena Chistyakova ◽  
Natalia Volkova ◽  
Ludmila Volkova ◽  
Baylar Iolchiev ◽  
...  

The aim of this study is to identify the effects of progesterone (PRG) on the capacitation and the acrosome reaction in bovine spermatozoa. The fresh sperm samples were incubated with and without capacitation inductors (heparin, dibutyryl cyclic adenosine monophosphate (dbcAMP)), hormones (prolactin (PRL), PRG), inhibitors of microfilaments (cytochalasin D) and microtubules (nocodazole) during capacitation and acrosome reactions. The functional status of spermatozoa was examined using the chlortetracycline assay. Supplementation of heparin stimulated capacitation in the presence and absence of PRG. Cytochalasin D blocked the stimulating effect of heparin on capacitation. The addition of PRL during capacitation (without PRG) did not affect the functional status of spermatozoa, while in PRG-treated cells PRL stimulated the acrosome reaction. PRL (with and without PRG) increased the acrosome reaction in capacitated cells. These PRL-dependent effects were inhibited by nocodazole. During the acrosome reaction, in presence of dbcAMP, PRG decreased the proportion of acrosome-reacted cells compared to PRG-untreated cells. This effect in PRG-treated cells was canceled in the presence of nocodazole. In conclusion, PRG under the action of PRL and dbcAMP determines the changes in the functional status of native sperm cells, which indicates PRG modulating effect on the indicators of post-ejaculatory maturation of spermatozoa.

Author(s):  
I. Chistyakova ◽  
V. Denisenko ◽  
T. Kuzmina

Purpose: investigate the effect of IBMX (activator of protein phosphorylation) and prolactin (PRL) on the functional state of cryopreserved bovine spermatozoa using inhibitory analysis.Materials and methods. Frozen-thawed semen samples from 60 black-and-white bulls was used in the experiments. For capacitation, cells were incubated in Sp-TALP medium supplemented with 6 mg/ml bovine serum albumin and various compounds: an inductor of capacitation (IBMX at concentrations of 1 μM, 10 μM, 50 μM, 100 μM), hormone (PRL at concentrations of 1 ng, 10 ng, 50 ng, 100 ng) and inhibitors of protein kinases C (Ro 31-8220 at a concentration of 10 ng/ml) and protein kinase A (H-89 at a concentration of 10 μM). The incubation was carried out at 38°C in an atmosphere of 5% CO2, 98% humidity for 4 hours. The functional status of the cells was determined by the chlortetracycline test.Results. It was shown that IBMX at all experimental concentrations did not affect the post-ejaculatory maturation (capacitation and acrosome reaction) of spermatozoa, while all concentrations of PRL (1-100 ng/ml) promoted the acrosome reaction in capacitated cells. In the presence of a protein kinase A inhibitor, there was a decrease in number of capacitated and an increase in number of acrosome-reactive spermatozoa under the action of IBMX at a concentration of 100 μM and no changes under the action of a protein kinase C inhibitor. Also, in case of protein kinase C inhibition the PRL-related stimulation of the acrosome reaction was canceled, while the usage of H-89 did not affect the functional status of spermatozoa, mediated by PRL. Thus, the influence of IBMX and PRL on the processes of post-ejaculatory maturation in thawed bovine spermatozoa was studied using the inhibitory analysis.Conclusion. At the capacital stage, all studied IBMX concentrations did not affect the ratio of deconved cells with various functional status. Prode also contributed to the passage of the acrosomous reaction in the rolled spermatozoa after defrosting. Inhibition of protein kinase A when incubating cells with IBMX has mediated the processes of acrosomal exocytosis in ripped cells and did not affect this process under the action of the PRR, while the protein kinase inhibitor C changed the ratio of cells with various functional status in the direction of increasing the percentage of cells at the rate of occasion I did not participate in intracellular action provided IBMX on deconved cells.


2020 ◽  
Vol 8 (4) ◽  
pp. 201-208
Author(s):  
Rahil Jannatifar ◽  
◽  
Hamid Piroozmanesh ◽  
Leila Naserpoor ◽  
◽  
...  

Background: This study aimed to explore whether the addition of a cyclic adenosine monophosphate (cAMP) analog and isobutylmethylxanthine (IBMX) in freezing media improved sperm quality and what role cAMP has in this recovery. Materials and methods: ach semen sample was cryopreserved into four groups: fresh semen sample, as a control group, freezing medium + 2.5 mM cAMP analog and 0.2 mM IBMX, freezing medium + 12.5 mM cAMP analog and 0.2 mM IBMX, and freezing medium + 25 mM cAMP analog and 0.2 mM IBMX. Sperm parameters after post-thaw were analyzed according to WHO instruction (2010). Viability, acrosome reaction, and DNA damage levels of the samples were evaluated. Results: Our results indicated that the effective concentrations of 12.5 and 25 mM cAMP analog and 0.2 mM IBMX significantly improved the total motility, progressive motility, and viability of the frozen-thawed (P<0.05). However, non-progressive motility and immotile were significantly reduced in the 12.5 and 25 mM cAMP analogs and 0.2 mM IBMX groups after thawing (P<0.05). During freezing the spermatozoa, the high concentration of the cAMP analog increased acrosome reaction after thawing in the 25 mM and 0.2 mM IBMX treated samples (P<0.05). DNA fragmentation in 25 mM cAMP analog and 0.2 mM (IBMX) supplementation was significantly lower compared to the other groups (P<0.05). Conclusions: Our findings revealed that in vitro cAMP analog and IBMX supplementation in freezing media play an important role in preventing cryodamage by maintaining the sperm functional parameters.


2019 ◽  
pp. 29-31
Author(s):  
I.V. CHISTIAKOVA ◽  
T.I. KUZMINA ◽  
V.Y. DENISENKO

Ранее нами было показано, что инкубация до замораживания сперматозоидов быков в присутствии соединений, увеличивающих количество капацитированных клеток [дибутирил циклический аденозинмонофосфат (dbcAMP), гепарин], после размораживания приводила к увеличению количества жизнеспособных клеток [2]. В данной работе исследовали влияние предварительной инкубации сперматозоидов быков до заморозки в присутствии соединений, увеличивающих количество акросома-реактивных клеток [пролактин (ПРЛ), гуанозинтрифосфат (ГТФ)], на жизнеспособность размороженных клеток. Если подготовленные подобным образом сперматозоиды использовать для искусственного оплодотворения, то в половых путях коров они попадут в среду, способствующую прохождению капацитации и будут там находиться в течение времени, достаточного для этого процесса. При повторной инкубации размороженных сперматозоидов активацию клеток проводили как в присутствии dbcAMP и IBMX (3-изобутил-1-метилксантин), так и ПРЛ и ГТФ. Повторная инкубация в течение 4 ч размороженных сперматозоидов быков, которые до замораживания обрабатывали совместным действием ПРЛ и ГТФ, приводила к увеличению количества жизнеспособных клеток как при добавлении dbcAMP и IBMX, так и ПРЛ и ГТФ. Определение с помощью хлортетрациклина местоположения флуоресценции в сперматозоидах показало, что повторная инкубация в течение 4 ч размороженных сперматозоидов не приводила к изменению соотношения числа клеток с различным функциональным статусом. Соотношение числа некапацитированных, капацитированных и акросома-реактивных клеток в интактных размороженных сперматозоидах и клетках, которые предварительно перед замораживанием обрабатывали ПРЛ и ГТФ, было одинаковым через 4 ч инкубации. Инкубация сперматозоидов быков до и после замораживания в присутствии индукторов акросомной реакции (ПРЛ и ГТФ) приводила к увеличению количества жизнеспособных клеток.It has been shown that the incubation of bovine spermatozoa before freezing in the presence of substances, which raise the number of capacitated cells [dibutyryl сyclic adenosine monophosphate (dbcAMP), heparin] after thawing led to the rise in number of viable cells [2]. In the present paper the effect of the preincubation of bull spermatozoa before freezing with substances increasing the number of acrosome-reactive cells (prolactin (PRL), guanosine triphosphate (GTP)) on their viability after thawing was examined. If spermatozoa, which are prepared by this way are used for artificial insemination, then in the reproductive tract of the cows they will fall into the environment which facilitates the passage of the capacitation and will remain there during sufficient time to undergo this process. With repeated incubation of thawed spermatozoa, the cell activation was performed both with dbcAMP and IBMX, and with PRL and GTP. The second 4 hours incubation of cells which were processed by PRL and GTP before freezing, led to the increase in the number of viable cells as with the addition of dbcAMP and IBMX, and PRL and GTP. The determination of fluorescence localization by chlortetracycline probe in sperm showed that the second incubation thawed spermatozoa for 4 hours did not lead to the change of the proportion of cells with different functional status. The ratio of uncapacitated, capacitated, and acrosome-reactive cells among intact thawed spermatozoa and cells which were previously treated by PRL and GTP before freezing was the same after 4 hours of the incubation. The preincubation of bovine spermatozoa before freezing with the acrosome reaction inductors (PRL and GTP) resulted to the increase in the number of viable cells.


2019 ◽  
Author(s):  
Bella Grigorenko ◽  
Igor Polyakov ◽  
Alexander Nemukhin

<p>We report a mechanism of adenosine triphosphate (ATP) to cyclic adenosine monophosphate (cAMP) conversion by the mammalian type V adenylyl cyclase revealed in molecular dynamics (MD) and quantum mechanics/molecular mechanics (QM/MM) simulations. We characterize a set of computationally derived enzyme-substrate (ES) structures showing an important role of coordination shells of magnesium ions in the solvent accessible active site. Several stable six-fold coordination shells of Mg<sub>A</sub><sup>2+ </sup>are observed in MD simulations of ES complexes. In the lowest energy ES conformation, the coordination shell of Mg<sub>A</sub><sup>2+ </sup>does not include the O<sub>δ1</sub> atom of the conserved Asp440 residue. Starting from this conformation, a one-step reaction mechanism is characterized which includes proton transfer from the ribose O<sup>3'</sup>H<sup>3' </sup>group in ATP to Asp440 via a shuttling water molecule and P<sup>A</sup>-O<sup>3A</sup> bond cleavage and O<sup>3'</sup>-P<sup>A</sup> bond formation. The energy profile of this route is consistent with the observed reaction kinetics. In a higher energy ES conformation, Mg<sub>A</sub><sup>2+</sup> is bound to the O<sub>δ1</sub>(Asp440) atom as suggested in the relevant crystal structure of the protein with a substrate analog. The computed energy profile initiated by this ES is characterized by higher energy expenses to complete the reaction. Consistently with experimental data, we show that the Asp440Ala mutant of the enzyme should exhibit a reduced but retained activity. All considered reaction pathways include proton wires from the O<sup>3'</sup>H<sup>3' </sup>group via shuttling water molecules. </p>


2019 ◽  
Vol 18 (1) ◽  
pp. 34-38
Author(s):  
Chen Lei ◽  
Pan Xiang ◽  
Shen Yonggang ◽  
Song Kai ◽  
Zhong Xingguo ◽  
...  

The aim of this study was to determine whether polydatin, a glucoside of resveratrol isolated from the root of Polygonum cuspidatum, warranted development as a potential therapeutic for ameliorating the pain originating from gallbladder spasm disorders and the underlying mechanisms. Guinea pig gallbladder smooth muscles were treated with polydatin and specific inhibitors to explore the mechanisms underpinning polydatin-induced relaxation of carbachol-precontracted guinea pig gallbladder. Our results shown that polydatin relaxed carbachol-induced contraction in a dose-dependent manner through the nitric oxide/cyclic guanosine monophosphate/protein kinase G and the cyclic adenosine monophosphate/protein kinase A signaling pathways as well as the myosin light chain kinase and potassium channels. Our findings suggested that there was value in further exploring the potential therapeutic use of polydatin in gallbladder spasm disorders.


2010 ◽  
Vol 18 (4) ◽  
pp. 6-8
Author(s):  
Stephen W. Carmichael

Some of the receptors on the surface of cardiac muscle cells (cardiomyocytes) mediate the response of these cells to catecholamines by causing the production of the common second messenger cyclic adenosine monophosphate (cAMP). An example of such receptors are the β1- and β2-adrenergic receptors (βARs) that are heterotrimeric guanine nucleotide-binding protein (G protein)-coupled receptors. Selective stimulation of these two receptor subtypes leads to distinct physiological and pathophysiological responses, but their precise location on the surface of cardiomyocytes has not been correlated with these responses. In an ingenious combination of techniques, Viacheslav Nikolaev, Alexey Moshkov, Alexander Lyon, Michele Miragoli, Pavel Novak, Helen Paur, Martin Lohse, Yuri Korchev, Sian Harding, and Julia Gorelik have mapped the function of these receptors for the first time.


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