The objective of this study was to examine the effect of various discontinuous Percoll washing conditions on sperm capacitation status and sperm survival. Frozen epididymal sperm samples from 3 bulls (0.5 ml plastic straws, 6% glycerol in egg yolk- Tris-glycerol extender) were thawed in 37℃ water bath for 1 min. To rule out individual variation, 3 sperm samples were mixed after thawing. The mixed samples then were randomly allocated to 12 treatment groups. Briefly, the spermatozoa were centrifuged for three different time lengths (10, 20, and 30 min) at two gravities (300 X g and 700 X g) through two concentrations of discontinuous Percoll density gradient of 1 ml 90%: 1 ml 45% Percoll and 2 ml 90%: 2 ml 45% Percoll to remove extender, debris, and dead spermatozoa. Sperm capacitation status and sperm survival were evaluated using combined Hoechst 33258 and chlortertracycline fluorescence staining assay. The acrosome reacted spermatozoa (AR pattern), uncapaciated spermatozoa (F pattern) and sperm survival were significantly correlated with centrifugation time (p< 0.01). Significantly decreased F pattern observed as centrifugal time increased. As centrifugal time increased, spermatozoa with F pattern decreased and spermatozoa showing AR pattern increased. Moreover, the dead spermatozoa were significantly stimulated in time-dependent manner. However, there were no significant differences in various force of centrifugation and Percoll volume. These results suggest that only centrifugation time significantly affects sperm capacitation status and sperm survival.

Voltage-dependent anion channel (VDAC) is mitochondrial protein of all eukaryotes. It has been reported that VDAC is a large voltage-dependent channel, regulation of ion (including Ca2+), and transportation of various metabolites. Ca2+ is an important factor in sperm function. In our previous study, we found high frequency of VDAC2 expression in spermatozoa from low-fertility bulls. However, to date, there is limited information available on its effects on male fertility. Therefore this experiment was designed to evaluate the effects of VDAC and Ca2+ on sperm function in vitro. To achieve this, four treatment conditions were established with or without Ca2+ and VDAC inhibitor, namely, 4’-diisothiocyano-2,2’-disulfonic acid stilbene (DIDS). Spermatozoa from adult ICR were collected and released into modified Tyrode’s salt media. And then, they were incubated in the different media with or without Ca2+and DIDS for 90 min at 37℃ in 5% CO2. Intracellular pH ([pH]i) and Ca2+ ([Ca2+]i) were measured by their fluorescent indicators, 2,7-bicarboxyethyl-5,6-carboxy- fluorescein acetoxymethyl ester (BCECF- AM) and fura-2 AM, respectively. Western blot of extracted sperm proteins with an anti-phosphotyrosine antibody (pY20) was carried out to determine tyrosine phosphorylation after sperm incubation in different treatments. To evaluate the fertilizing ability after treatments, in vitro fertilization was performed. DIDS significantly decreased [Ca2+]i regardless of Ca2+. [pH]i was efficiently affected by the presence of Ca2+ and/or DIDS. However, the highest decrease of pH level was observed under the presence of DIDS and the absence of Ca2+ in culture condition. Tyrosine phosphorylated protein 1 was significantly different under all treatments. However, tyrosine phosphorylated protein 2 was not significantly different under the presence of DIDS. Fertilization rate was significantly decreased under the presence of DIDS. Blastocyst formation was significantly altered different to compare to control and each treatment group. Therefore it suggests that a voltage-dependent anion channel may involved paramount importance in regulation of male fertility.

Phosphorylation of proteins is a post-translational modification process which plays a significant role in a wide range of cellular processes. Addition or removal of phosphate groups result in conformational changes in proteins leading either to their activation or inactivation. Tyrosine phosphorylation of protein is associated with sperm function in several mammalian species. The control of this process may via the changes in cyclic adenosine monophosphate (cAMP); the changes in cAMP levels that occur in the spermatozoa regulate protein kinase A (PKA) activity which, in turn, leads to the tyrosine phosphorylation of protein substrates by either the activation of sperm tyrosine kinases and/or the inhibition of phosphoprotein phosphatases. Cyclic nucleotides, in particular, cAMP, are important regulators of various maturation events in sperm including capacitation and motility. Interestingly, some environmental chemicals (ECs) may exert broader endocrine disrupting effects through possible modulation of cAMP/PKA second messenger systems. Otherwise, because the mature spermatozoa are transcriptionally inactive, therefore the study of sperm proteins phosphorylation may permit more information about the agents and conditions affects on sperm function. In the present study, to examine the effect of ECs on human sperm function, human spermatozoa were incubated with a group of ECs represent a widespread chemicals in the environment bisphenol A (BPA, 100 μM), nonylphenol (NP, 10 μg/ml), 2,3,7,8-Tetrachlorodibenzo- pdioxin (TCDD, 2.5 μg/ml), genistein (Gen, 100 μM), and the following pesticides, dibromochloropropane (DBCP, 10 μg/ml), atrazine (Atraz, 500 μM), and diazinone (Diaz, 500 μM) for 6 hr at 37℃ in 5% CO2. Then, western blot analysis was carried out using extracted sperm proteins. Antiphosphorylation antibody (pY20) was used to determine sperm tyrosine phosphorylation after EDs treatment. The pY20 antibody labeled three common bands of approximately 90, 110, and 150 KDa. There were no significant differences between negative and positive control groups in regard to the tyrosine phosphorylated proteins except at the band with molecular weight 110 KDa. However, except Diaz treatment group, the other treatment groups showed decreasing (TCDD, Gen, NP, BPA, and DBCP) or increasing (Atraz) in the tyrosine phosphorylated proteins at least in one band from the three common bands studied. Therefore, it sug-gests that ECs effectively alters human sperm function and this effect may detect via their effect on tyrosine phosphorylation pattern.

In mammals, the meiosis division in testes produces equal numbers of two different types of gametes: X chromosome-bearing sperm (X-spermatozoa) and Y chromosomebearing sperm (Y-spermatozoa), which have equal potential to fertilize the oocytes. Therefore, the expected 1: 1 sex ratio is observed. However, under some conditions like endocrine disruptors (EDs) exposure the sex ratio is deviated than the expected with more males or more females. And recently many hypotheses have been postulated to explain the mechanism of sex ratio deviation; however none of them introduced a proven experimental explanation. To solve this enigma, we hypothesized that the differences between X- and Y-spermatozoa survivability under specific conditions due to differences in their chromosome contents are the key leading to the sex ratio alteration. To examine our hypothesis, we combined two techniques; first, hypo-osmotic swelling (HOS) test that was applied to test viability of spermatozoa and second, fluorescence in situ hybridization that was applied on HOS-treated spermatozoa to define sex chromosome composition. In the present study, human spermatozoa were incubated with a group of EDs represent a widespread chemicals in the environment bisphenol A (BPA, 100 μM), nonylphenol (NP, 10 μg/ml), 2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD, 2.5 μg/ml), genistein (Gen, 100 μM), and the following pesticides, dibromochloropropane (DBCP, 10 μg/ml), atrazine (Atraz, 500 μM), and diazinone (Diaz, 500 μM) for 6 hr at 37℃ in 5% CO2. Then, the viability of spermatozoa and their sex chromosome contents were evaluated simultaneously. Among seven chemicals studied only four chemicals (Atraz, DBCP, TCDD, and Diaz) significantly decreased Y-sperm viability when compared to those of X-spermatozoa in the same treatment group and viability of Y-spermatozoa when compared to those in the negative and positive (DMSO) control groups (p<0.05). Also, in these four treatment groups the sex ratio of live sperm population was significantly lowered compared to the control groups (p<0.05). Otherwise, Gen, BPA, and NP did not show any significant effect on viability of Yspermatozoa or decreasing sex ratio in live sperm population as compared to the control groups. It has been proven that TCDD, DBCP, and the pesticides decrease the sex ratio, but the same effect was not observed in case of Gen, BPA, and NP. From the present findings, there is no doubt that the EDs may alter sex ratio via decreasing Y-spermatozoa viability.

In the last few decades with the industrial revolution many environmental contaminants have estrogenic activity (endocrine disruptors, EDs) are released into the environment affecting the male reproductive system and male fertility. Sperm motility is one of the initial tests performed to assess sperm function; only motile sperm can achieve fertilization in vivo. The present study aimed to investigate the possible effects of a group of EDs that represent a widespread chemicals in the environment genistein (Gen), is a naturally occurring isoflavone (100 μM), bisphenol A (BPA), that is used in the manufacture of plastics and other products and released largely into the environment (100 μM), nonylphenol (NP) is an important environmental toxicant and potential endocrine disrupting chemical (10 μg/ml), TCDD, that is formed as an unwanted by-product in the manufacture of chlorinated hydrocarbons (2.5 μg/ml), atrazine (Atraz) is a herbicides (500 μM), dibromochloropropane (DBCP) is a pesticide (10 μg/ml), and diazinone (Diaz) is a insecticide (500 μM) on human sperm motility and kinematic characteristics. Human spermatozoa were incubated in Ham's F10 media with/without the tested chemicals or DMSO as positive control for 6 hr at 37℃ in 5% CO2. Then, sperm motility was assessed using computer assisted semen analyzer. Interestingly, all the chemicals tested significantly decreased sperm motility as compared to the control groups. However, only Diaz significantly decreased sperm kinematic characteristics namely, VCL, VSL, STR, VAP, and ALH. We suggest that the environmental chemicals may have an effect on male fertility via decreasing sperm motility.

The objective of this study was to examine the effect of various discontinuous Percoll washing conditions on motile sperm recovery rate and motion kinematics. Frozen semen samples from 3 bulls (0.5 ml plastic straws, 6% glycerol in egg yolk-Tris-glycerol extender) were thawed in 37℃ water bath for 1 min. After thawing, the mixed semen samples were randomly allocated to 12 treatment groups. Briefly, the spermatozoa were centrifuged for three different time lengths (10, 20, and 30 min) at two gravities (300×g and 700×g) through two concentrations of discontinuous Percoll density gradient of 1 ml 90%: 1 ml 45% Percoll and 2 ml 90%: 2 ml 45% Percoll to remove extender, debris, and dead spermatozoa. Motile sperm recovery rate and motion kinematics were evaluated by computer assisted sperm analyzer using Makler counting chamber. Sperm motility (%) and motile sperm recovery rate showed similar pattern in all treatment groups. However, sperm motility (%) and motile sperm recovery rate were highest at 700×g for 30 min through a discontionous Percoll density gradient of 1 ml 90%: 1 ml 45% Percoll. There were no significant differences in motion kinematics after various Percoll washings. These results suggest that force of centrifugation, centrifugation time, and Percoll volume significantly affect motile sperm recovery rate.

Endocrine disruptors bind to hormone receptors on sperm membrane, therefore spermatozoa are potentially a useful model for examining estrogenic activities of endocrine disruptors. The objective of this study was to compare the effects of two xenoestrogenic compounds [genistein (Gen) and 4-tert-octylphenol (OP)] to those of two steroids [estrogen (E2) and progesterone (P4)] on boar sperm % motility and motion kinematics of in vitro. Porcine spermatozoa were incubated with various concentrations (0.001～100 μM) of each chemical for 15 or 30 min, and then assessed % motility and sperm motion kinematics using computer assisted sperm analyzer (CASA). Each chemical decreased sperm % motility, and OP decreased VSL and VAP compared with untreated control(p<0.05). E2 stimulated the motion kinematic changes except VCL. Moreover, Gen had effects on VCL and VAP alterations after 30 min incubation. In summary, since all chemicals studied effectively altered sperm % motility and motion kinematics, it was concluded that porcine spermatozoa could be a useful model for in vitro screening of potential endocrine disruptors.