جستجوی مقالات مرتبط با کلیدواژه « Acrosome reaction » در نشریات گروه « پزشکی »

Transient receptor potential vanilloid 1 (TRPV1) is a heat-activated nonselective cation channel that playsimportant role in the spermatogenesis, capacitation, acrosome reaction and sperm/oocyte fusion. Considering the hightesticular temperature and oxidative stress in varicocele condition, we aimed to assess expression of TRPV1 in sperm of infertile men.

In this case-control study, twenty-five men with varicocele (grade II and III) as well as twentyfivefertile were recruited. Sperm parameters, protamine deficiency (Chromomycin A3), DNA damage (TUNEL), lipid peroxidation (BODIPY), TRPV1 gene expression (real time polymerase chain reaction), TRPV1 protein (flowcytometry and immunocytochemical techniques), and acrosome reaction were assessed between fertile and varicocele groups.

We observed a significant decrease in the sperm parameters, and also, an increased DNA damage, lipid peroxidation, and protamine deficiency in varicocele group. Although, the mRNA expression of TRPV1 was similar between varicocele and fertile groups, its expression at the protein level was significantly decreased in the varicocele group in comparison with fertile group. Additionally, the TRPV1 localization was changed from the equatorial region to the acrosomal region of the head, especially in the acrosomal region, which was more significant in the fertile group than the varicocele group after inducing acrosome reaction.

In addition to the quality of sperm parameters, and chromatin integrity that were lower significantly in varicocele group, the expression of TRPV1 protein was also lower in varicocele condition that could be associated with reduced capacitation, acrosome reaction and sperm/oocyte fusion and thereby infertility.

Calcium (Ca) is a significant element that acts as an intracellular second messenger. It is necessary for many physi- ological processes in spermatozoa including spermatogenesis, sperm motility, capacitation, acrosome reaction and fertilization. Although influences of Ca deficiency on sperm function and male infertility have been widely studied, mechanisms for these abnormalities are not well considered. Poor sperm motility, impairment of chemotaxis, capaci- tation, acrosome reaction and steroidogenesis are the major mechanisms by which Ca deficiency induces male infertil- ity. Therefore, an optimal seminal Ca concentration is required to strengthen sperm function and all steps leading to successful fertilization. Furthermore, identification of these mechanisms provides valuable information regarding the mechanisms of Ca deficiency on male reproductive system and the way for developing a better clinical approach. In this review, we aim to discuss the proposed cellular and molecular mechanisms of Ca deficiency on male reproductive system, sperm function and male fertility. Also we will discuss the valuable information currently available for the roles of Ca in male reproduction.

Intracellular calcium and proton concentrations are important factors for activating human sperm. Calcium ion (Ca2) enters sperm through voltage-dependent calcium channel of sperm (CatSper). Proton was extruded from sperm through voltage-gated proton channel (Hv1). In the present study, the selective inhibitors of the CatSper and Hv1 channels, NNC 55-0396 (NNC) and zinc ion, respectively, were used to investigate functions of these channels.
Normal semen samples (n=24) were washed and diluted to 20×106 sperm/ml. The diluted sample was divided into 8 groups, containing Ham’s F-10 (the control group), 2 µM NNC, 1 mM ZnCl2 and NNC. The other 4 groups were the same as above, except that they contained 1 µM progesterone. The computer assisted analysis was done by VT-Sperm 3.1 to determine the percentage of motile sperm and sperm velocity. Acrosomal status was monitored by FITC-PSA and viability assessed by Eosin–Y staining. Statistical comparisons were made using ANOVA followed by Tukey post hoc test. The p The percentage of viable and motile sperm, curvilinear velocity and other parameters of motility was reduced in all groups containing NNC, zinc and NNC츩. Progesterone–induced acrosome reaction was abolished by each of these inhibitors. The combination effect of NNC plus zinc on motility and progesterone–induced acrosome reaction was not stronger than NNC by itself.
CatSper and Hv1 channels play a critical role in human sperm function and viability. It seems that a functional relationship exists between CatSper and Hv1 channels.

Low levels of reactive oxygen species (ROS) and calcium are necessary for sperm function. NADPH oxidase 5 (NOX5) is a membrane enzyme which produces ROS. This enzyme is dependent on calcium for its activity. We investigated the importance of NOX5 and an important calcium channel (CatSper) on sperm function.
This laboratory in-vitro study was done in Shiraz, Iran, 2016. Normal semen samples (n=24) were washed and diluted to 20×106 sperm/mL. The diluted samples were divided into 8 groups, containing Ham’s F-10 (control group), 2 µM of NNC (CatSper channel inhibitor), 1 µM DPI (NOX5 inhibitor), and NNCೲ. The other 4 groups were the same as the 1st ones, except that they contained 1 µM of progesterone. Motility assessment was done by VT–Sperm 3.1. Acrosome status was monitored with acrosome-specific FITC-PSA using fluorescent microscopy. Sperm viability was assessed by Eosin Y. Statistical analysis was performed using SPSS 16 software. The comparison between the groups was done using the one-way ANOVA, followed by Tukey. A P The percentage of motile sperm, sperm velocity, and viability decreased significantly in the groups containing NNC. DPI reduced sperm progressive motility only in the progesterone-stimulated condition. Progesterone induced acrosome reaction, but this effect was inhibited by NNC and DPI.
CatSper had a prominent role in the motility, acrosome reaction, and viability of the human sperm. The function of NOX5 was important only in the stimulated sperm. We conclude that CatSper has a more prominent role than NOX5 activity. The functional relation between NOX5 and CatSper is not clear but is very probable.

The freezing and thawing process not only is associated with serious damage to sperm such as damage to the plasma membrane and the acrosomal membrane but also changes the membrane permeability to some ions including calcium. Also, the generation of oxygen free radicals is increased during the freezing-thawing process. The purpose of this study was to evaluate of the effects of Trolox as an antioxidant and edetic acid (EDTA) as a calcium chelator on frozen-thawed (FT) sperm and compare these effects with those on fresh sperm. This study was done on these men of 25 healthy men, who referred to Shiraz Infertility Centerbetween2012 and2013. Normal samples were transferred to the ReproductivePhysiology Laboratory, Department of Physiology,Shiraz University of Medical Sciences, Shiraz. The samples were divided into two groups randomly: fresh and FT sperm groups. Each group was divided into five subgroups:control group, the solvent group (0.1%dimethyl sulfoxide [DMSO]), Trolox group (200μM), EDTA group (1.1mM), and Troloxဴ group. The percentages of motility, viability, and acrosome-reacted sperm were tested. The percentages of motility and viability in the FT sperm were lower than those in the fresh sperm. The progressive motility of the FT sperm was improved nonsignificantly with Troloxဴ. However, the effect of Troloxဴ on the progressive motility of the FT sperm was much more than that on the fresh sperm. The fewest acrosome-reacted sperm were observed in the EDTA-containingFT sperm. Antioxidant supplementation or omission of extracellular calcium may partly improve motility and also reduce acrosomal damage in FT sperm.

Oxidative stress in teratozoospermic semen samples caused poorassisted reproductive techniques (ART) outcomes. Among antioxidants, ascorbicacid is a naturally occurring free radical scavenger and as such its presence assistsvarious other mechanisms in decreasing numerous disruptive free radical processes. The main goal of this study was to evaluate potential protective effects of ascorbic acid supplementation during in vitro culture of teratozoospermic specimens. Teratozoospermic semen samples that collected from 15 volunteers were processed, centrifuged and incubated at 37PoPC until sperm swimmed-up. Supernatant was divided into four groups and incubated at 37PoPC for one hour under different experimental conditions: Control, 10 μm A23187, 600μm ascorbic acid and 10 μm A23187+600 μm ascorbic acid. After incubation sperm motility, viability, acrosome reaction, DNA damage and malondialdehyde levels were evaluated. Our results indicated that after one hour incubation, ascorbic acid significantly reduced malondialdehyde level in ascorbic acid group (1.4±0.11 nmol/ml) compared to control group (1.58±0.13 nmol/ml) (p<0.001). At the end of incubation, progressive motility and viability in ascorbic acid group (64.5±8.8% and 80.3±6.4%, respectively) were significantly (p<0.05 and p<0.001, respectively) higher than the control group (54.5±6.8% and 70.9±7.3%, respectively). A23187 significantly (p<0.0001) increased acrosome reaction in A23187 group (37.3±5.6%) compared to control group (8.5±3.2%) and this effect of A23187 attenuated by ascorbic acid in ascorbic acid+A23187 group (17.2±4.4%). DNA fragmentation in ascorbic acid group (20±4.1%) was significantly (p<0.001) lower than controls (28.9±4.6%). In vitro ascorbic acid supplementation during teratozoospermic semenprocessing for ART could protect teratozoospermic specimens against oxidativestress, and it could improve ART outcome.

Nanoparticles have wide range of application while there are some reports regarding their probable effects on male reproductive system and spermatozoa.

The aim of this study was to evaluate the effect of different doses of silver nanoparticles (AgNPs) (70nm) on acrosome of rat spermatozoa and number of spermatogenic cells.

In this experimental study, in experimental group, 32 male wistar rats (8 rats/group) received oral feeding AgNPs every 12 hr in one spermatogenesis period (48 days) by means of gavages in 25, 50, 100 and 200 mg/kg concentration (experimental groups 1-4, respectively). The control group (8 rats) was treated on schedule with distilled water. Spermatozoa were stained by triple staining protocol for acrosome reaction. Histological evaluation on testis sections was performed using tissue processing and hematoxylin-eosin (H&E) staining.

There was significant difference between the control group and the experimental group 1 for acrosome reaction (11.00±0.00 and 24.25±3.68, respectively, p=0.01). There was only significant reduction in spermatogonia cells in experimental group 4. Experimental groups 2, 3 and 4 showed a significant reduction in the number of primary spermatocytes and spermatids as well as spermatozoa. But there were no significant differences between different groups for Sertoli cell number and seminiferous tubule diameter.

It seems that Ag NPs have acute and significant effects on spermatogenesis and number of spermatogenic cells and also on acrosome reaction in sperm cells. More experimental investigations are necessary to elucidate better conclusion regarding the safety of nanoparticles on male reproduction system.