Membrane Potential Assessment by Fluorimetry as a Predictor Tool of Human Sperm Fertilizing Capacity

Background: Acrylamide (AA) is a compound used in the industrial production of polyacrylamide. AAs affects by creating oxidative stress. It produces reactive oxygen species and leads to lipid peroxide. Lipid peroxidation in the cell membrane is one of the most important oxidations in the sperm, which can disrupt the fluidity and permeability of cell membranes and damage all cells. Objective: To investigate the different concentrations of AA on human sperm parameters based on the World Health Organization standard and its impact on mitochondrial membrane potential and sperm glutathione levels. Materials and Methods: In this laboratory study, we examined the different concentrations of AA on human sperm parameters based on the World Health Organization standard and its impact on mitochondrial membrane potential by flow cytometry and sperm glutathione levels by ELISA assay. Results: The results were reported as the mean fluorescence intensity of JC and the index was observed to decrease following the effect of AA in mitochondrial membrane potential (Δ Ψm). The results of ELISA test to study the level of intracellular glutathione showed that with the increase in the concentration of AA exposed to sperms, there was a significant reduction in the level of intracellular glutathione. Conclusion: AA destroys the sperm membrane integrity under apoptotic and oxidative inductions with a negative impact on mitochondrial function and antioxidative enzyme in sperm such as glutathione. Key words: Acrylamides, Spermatozoa, Mitochondrial membrane potential, Glutathione S-Transferase.

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[Ca2+]i oscillations in human sperm are triggered in the flagellum by membrane potential-sensitive activity of CatSper

Human Reproduction ◽

10.1093/humrep/deaa302 ◽

2020 ◽

Author(s):

Elis Torrezan-Nitao ◽

Sean G Brown ◽

Esperanza Mata-Martínez ◽

Claudia L Treviño ◽

Christopher Barratt ◽

...

Keyword(s):

Membrane Potential ◽

Large Scale ◽

Conflicts Of Interest ◽

Human Sperm ◽

Equilibrium Potential ◽

Current Clamp ◽

Whole Cell ◽

Cell Current ◽

Whole Cell Current

Abstract STUDY QUESTION How are progesterone (P4)-induced repetitive intracellular Ca2+ concentration ([Ca2+]i) signals (oscillations) in human sperm generated? SUMMARY ANSWER P4-induced [Ca2+]i oscillations are generated in the flagellum by membrane potential (Vm)-sensitive Ca2+-influx through CatSper channels. WHAT IS KNOWN ALREADY A subset of human sperm display [Ca2+]i oscillations that regulate flagellar beating and acrosome reaction. Although pharmacological manipulations indicate involvement of stored Ca2+ in these oscillations, influx of extracellular Ca2+ is also required. STUDY DESIGN, SIZE, DURATION This was a laboratory study that used >20 sperm donors and involved more than 100 separate experiments and analysis of more than 1000 individual cells over a period of 2 years. PARTICIPANTS/MATERIALS, SETTING, METHODS Semen donors and patients were recruited in accordance with local ethics approval from Birmingham University and Tayside ethics committees. [Ca2+]i responses and Vm of individual cells were examined by fluorescence imaging and whole-cell current clamp. MAIN RESULTS AND THE ROLE OF CHANCE P4-induced [Ca2+]i oscillations originated in the flagellum, spreading to the neck and head (latency of 1–2 s). K+-ionophore valinomycin (1 µM) was used to investigate the role of membrane potential (Vm). Direct assessment by whole-cell current-clamp confirmed that Vm in valinomycin-exposed cells was determined primarily by K+ equilibrium potential (EK) and was rapidly ‘reset’ upon manipulation of [K+]o. Pre-treatment of sperm with valinomycin ([K+]o = 5.4 mM) had no effect on the P4-induced [Ca2+] transient (P = 0.95; eight experiments), but application of valinomycin to P4-pretreated sperm suppressed activity in 82% of oscillating cells (n = 257; P = 5 × 10−55 compared to control) and significantly reduced both the amplitude and frequency of persisting oscillations (P = 0.0001). Upon valinomycin washout, oscillations re-started in most cells. When valinomycin was applied in saline with elevated [K+], the inhibitory effect of valinomycin was reduced and was dependent on EK (P = 10−25). Amplitude and frequency of [Ca2+]i oscillations that persisted in the presence of valinomycin showed similar sensitivity to EK (P < 0.01). The CatSper inhibitor RU1968 (4.8 and 11 µM) caused immediate and reversible arrest of activity in 36% and 96% of oscillating cells, respectively (P < 10−10). Quinidine (300 µM) which blocks the sperm K+ current (IKsper) completely, inhibited [Ca2+]i oscillations. LARGE SCALE DATA N/A LIMITATIONS, REASONS FOR CAUTION This was an in-vitro study and caution must be taken when extrapolating these results to in-vivo regulation of sperm. WIDER IMPLICATIONS OF THE FINDINGS [Ca2+]i oscillations in human sperm are functionally important and their absence is associated with failed fertilisation at IVF. The data reported here provide new understanding of the mechanisms that underlie the regulation and generation (or failure) of these oscillations. STUDY FUNDING/COMPETING INTEREST(S) E.T.-N. was in receipt of a postgraduate scholarship from the CAPES Foundation (Ministry of Education, Brazil). E.M-M received travel funds from the Programa de Apoyo a los Estudios de Posgrado (Maestria y Doctorado en Ciencias Bioquimicas-Universidad Autonoma de Mexico). SGB and CLRB are recipients of a Chief Scientist Office (NHS Scotland) grant TCS/17/28. The authors have no conflicts of interest.

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Candida albicans experimental infection: effects on human sperm motility, mitochondrial membrane potential and apoptosis

Reproductive BioMedicine Online ◽

10.1016/s1472-6483(10)60125-3 ◽

2009 ◽

Vol 18 (4) ◽

pp. 496-501 ◽

Cited By ~ 19

Author(s):

Nunziatina Burrello ◽

Mario Salmeri ◽

Anna Perdichizzi ◽

Salvatore Bellanca ◽

Giuseppe Pettinato ◽

...

Keyword(s):

Candida Albicans ◽

Membrane Potential ◽

Mitochondrial Membrane Potential ◽

Sperm Motility ◽

Experimental Infection ◽

Mitochondrial Membrane ◽

Human Sperm

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High glucose concentrations per se do not adversely affect human sperm function in vitro

Reproduction ◽

10.1530/rep-15-0100 ◽

2015 ◽

Vol 150 (1) ◽

pp. 77-84 ◽

Cited By ~ 11

Author(s):

J M D Portela ◽

R S Tavares ◽

P C Mota ◽

J Ramalho-Santos ◽

S Amaral

Keyword(s):

Membrane Potential ◽

High Glucose ◽

Human Sperm ◽

Superoxide Production ◽

Integrated Analysis ◽

Sperm Function ◽

Reproductive Dysfunction ◽

Per Se ◽

Acrosomal Integrity

Diabetes mellitus (DM) represents one of the greatest concerns to global health and it is associated with diverse clinical complications, including reproductive dysfunction. Given the multifactorial nature of DM, the mechanisms that underlie reproductive dysfunction remain unclear. Considering that hyperglycemia has been described as a major effector of the disease pathophysiology, we used anin vitroapproach to address the isolated effect of high glucose conditions on human sperm function, thus avoiding otherin vivoconfounding players. We performed a complete and integrated analysis by measuring a variety of important indicators of spermatozoa functionality (such as motility, viability, capacitation status, acrosomal integrity, mitochondrial superoxide production and membrane potential) in human sperm samples after incubation withd- andl-glucose (5, 25, or 50 mM) for 24 and 48 h. No direct effects promoted by 25 or 50 mMd-glucose were found for any of the parameters assessed (P>0.05), except for the acrosome reaction, which was potentiated after 48 h of exposure to 50 mMd-glucose (P<0.05). Interestingly, non-metabolizablel-glucose drastically increased superoxide production (P<0.05) and suppressed sperm motility (P<0.05) and capacitation (P<0.05) after 24 h of treatment, whereas mitochondrial membrane potential (P<0.05), acrosomal integrity (P<0.01) and viability (P<0.05) were later decreased. The overall results suggest that high glucose levelsper sedo not influence human sperm functionin vitro, which stresses the importance of other factors involved in DM pathology. Nevertheless, the absence of metabolizable glucose contributes to a severe impairment of sperm function and thus compromises male fertility.Free Portuguese abstract: A Portuguese translation of this abstract is freely available athttp://www.reproduction-online.org/content/150/1/77/suppl/DC1.

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