In Utero Exposure to Metformin Reduces the Fertility of Male Offspring in Adulthood

Metformin is a drug used for the treatment of type 2 diabetes and disorders associated with insulin resistance. Metformin is also used in the treatment of pregnancy disorders such as gestational diabetes. However, the consequences of foetal exposure to metformin on the fertility of exposed offspring remain poorly documented. In this study, we investigated the effect of in utero metformin exposure on the fertility of female and male offspring. We observed that metformin is detectable in the blood of the mother and in amniotic fluid and blood of the umbilical cord. Metformin was not measurable in any tissues of the embryo, including the gonads. The effect of metformin exposure on offspring was sex specific. The adult females that had been exposed to metformin in utero presented no clear reduction in fertility. However, the adult males that had been exposed to metformin during foetal life exhibited a 30% reduction in litter size compared with controls. The lower fertility was not due to a change in sperm production or the motility of sperm. Rather, the phenotype was due to lower sperm head quality - significantly increased spermatozoa head abnormality with greater DNA damage - and hypermethylation of the genomic DNA in the spermatozoa associated with lower expression of the ten-eleven translocation methylcytosine dioxygenase 1 (TET1) protein. In conclusion, while foetal metformin exposure did not dramatically alter gonad development, these results suggest that metabolic modification by metformin during the foetal period could change the expression of epigenetic regulators such as Tet1 and perturb the genomic DNA in germ cells, changes that might contribute to a reduced fertility.

Preconception seminal plasma concentrations of endocrine disrupting chemicals in relation to semen quality parameters among male partners planning for pregnancy

BACKGROUND

Some non-persistent endocrine disruptors (EDCs) are adversely associated with semen quality and few studies have measured those EDCs in seminal plasma.

OBJECTIVE

To find an association between EDCs in seminal plasma and semen quality parameters.

METHODS

Five chemical classes of non-persistent EDCs were quantified in seminal plasma from 339 male partners who participated in a prospective pregnancy study. Bisphenols, benzophenone UV-filters, antimicrobials and phthalate diesters and their monoester metabolites were measured using high performance liquid chromatography-tandem mass spectrometry and gas chromatography-mass spectrometry. Semen samples underwent next day analysis using a standardized protocol for the quantification of 35 endpoints. Linear mixed-effects models of EDCs that were log transformed and rescaled by their standard deviations or dichotomized at the 75th percentile for each exposure and outcomes with covariate adjustment were performed. EDCs in seminal plasma were also assessed relative to clinical reference values of semen quality endpoints using logistic regression or generalized estimating equations.

RESULTS

The most consistent findings supporting adverse associations between seminal EDCs and semen quality were observed for some phthalate metabolites. For example, seminal plasma mono-ethyl, mono-n-butyl, mono-2-isobutyl and mono-benzyl phthalate concentrations were associated with decreased odds of having semen volume above clinical reference values (mEP: aOR=0.46; 95%CI= 0.32, 0.66; mBP: aOR=0.40; 95%CI= 0.28, 0.57; miBP: aOR=0.39; 95%CI= 0.27, 0.56), and mBzP: aOR= 0.34; 95%CI= 0.24, 0.49).

CONCLUSIONS

Environmentally relevant concentrations of specific phthalates in seminal plasma were associated with diminished semen volume, sperm motility, viability, and morphological alterations in sperm heads such that semen volume and sperm viability fall below reference values.

Effects of In Utero and Lactational Exposure to New Generation Green Plasticizers on Adult Male Rats: A Comparative Study With Di(2-Ethylhexyl) Phthalate

Di(2-ethylhexyl) phthalate (DEHP), a widely used plasticizer, is a ubiquitous environmental contaminant and may act as an endocrine disruptor. Early life exposures to DEHP may result in anti-androgenic effects, impairing the development of the male reproductive tract. However, data on the long-lasting consequences of such DEHP exposures on adult male reproductive function are still rare and discrepant. Previously, we identified 2 novel plasticizers, 1,4-butanediol dibenzoate (BDB) and dioctyl succinate (DOS), as potential substitutes for DEHP that did not reproduce classically described endocrine disrupting phenotypes in prepubertal male offspring after maternal exposure. Here, we investigated the consequences of in utero and lactational exposure to BDB and DOS on adult male rat reproductive function in a comparative study with DEHP and a commercially available alternative plasticizer, 1,2-cyclohexane dicarboxylic acid diisononyl ester (DINCH). Timed pregnant Sprague Dawley rats were gavaged with vehicle or a test chemical (30 or 300 mg/kg/day) from gestation day 8 to postnatal day 21. While DEHP exposure (300 mg/kg/day) significantly increased epididymal weight in the adult, exposure to DINCH, BDB, or DOS did not affect reproductive organ weights, steroid levels, or sperm quality. Using a toxicogenomic microarray approach, we found that adult testicular gene expression was affected by exposure to the higher dose of DEHP; transcripts such as Nr5a2, Ltf, or Runx2 were significantly downregulated, suggesting that DEHP was targeting estrogen signaling. Lesser effects were observed after treatment with either DINCH or BDB. DOS exposure did not produce such effects, confirming its potential as a responsible substitute for DEHP.

Male urinary paracetamol and semen quality

The endocrine-disrupting properties of paracetamol have been previously demonstrated in rodent studies of abnormal sperm morphology and diminished testosterone production, in addition to epidemiologic studies of diminished couple fecundity. In this study, we examined the relationship between paracetamol and its metabolite p-aminophenol quantified in a single spot urine and semen quality among 501 male partners of couples planning for pregnancy. Men provided a urine specimen and two fresh semen samples collected approximately one month apart and underwent 24-h analysis for 35 semen quality parameters. Paracetamol and p-aminophenol were quantified in urine by ultra-high-performance liquid chromatography coupled with an electrospray triple quadrupole mass spectrometry. The relationship between natural-log-transformed urinary paracetamol and p-aminophenol rescaled by their standard deviation and 21 Box-Cox-transformed, 14 non-transformed semen parameters was assessed using linear mixed-effects models. The median concentrations (IQR) of urinary paracetamol and p-aminophenol were 15.5 ng/mL (5.44, 73.5) and 978 ng/mL (500, 1596), respectively. Following adjustment for creatinine and age, a 1-standard deviation increase in log-transformed urinary paracetamol was associated with a reduction in beat cross-frequency and an increase in DNA fragmentation [β (95% CI): -0.59 Hz (-1.16, -0.03) and 0.05% (0.01, 0.09), respectively]. These findings were corroborated in models of categorical chemical concentrations; higher concentrations of paracetamol remained associated with reduced beat cross-frequency and increased DNA fragmentation. A 1-standard deviation increase in log-transformed urinary p-aminophenol was associated with a reduction in sperm head area [β (95% CI): -0.1 μm2 (-0.18, -0.02) and width -0.02 μm (-0.04, -0.01)]. However, only the association with sperm head area remained statistically significant in models of p-aminophenol quartiles. Our findings suggest that adult male urinary paracetamol is associated with sperm motility and DNA fragmentation, while the metabolite, p-aminophenol, is predominantly associated with sperm head morphometry.

Comparative proteome analysis of cryopreserved flagella and head plasma membrane proteins from sea bream spermatozoa: effect of antifreeze proteins

Cryopreservation induces injuries to fish spermatozoa that in turn affect sperm quality in terms of fertilization ability, motility, DNA and protein integrity and larval survival. To reduce the loss of sperm quality due to freezing-thawing, it is necessary to improve these procedures. In the present study we investigated the ability of two antifreeze proteins (AFPI and AFPIII) to reduce the loss of quality of sea bream spermatozoa due to cryopreservation. To do so, we compared viability, motility, straight-line velocity and curvilinear velocity of fresh and (AFPs)-cryopreserved spermatozoa. AFPIII addition to cryopreservation medium improved viability, motility and straight-line velocity with respect to DMSO or DMSO plus AFPI. To clarify the molecular mechanism(s) underlying these findings, the protein profile of two different cryopreserved sperm domains, flagella and head plasma membranes, was analysed. The protein profiles differed between fresh and frozen-thawed semen and results of the image analysis demonstrated that, after cryopreservation, out of 270 proteins 12 were decreased and 7 were increased in isolated flagella, and out of 150 proteins 6 showed a significant decrease and 4 showed a significant increase in head membranes. Mass spectrometry analysis identified 6 proteins (4 from isolated flagella and 2 present both in flagella and head plasma membranes) within the protein spots affected by the freezing-thawing procedure. 3 out of 4 proteins from isolated flagella were involved in the sperm bioenergetic system. Our results indicate that the ability of AFPIII to protect sea bream sperm quality can be, at least in part, ascribed to reducing changes in the sperm protein profile occurring during the freezing-thawing procedure. Our results clearly demonstrated that AFPIII addition to cryopreservation medium improved the protection against freezing respect to DMSO or DMSO plus AFPI. In addition we propose specific proteins of spermatozoa as markers related to the procedures of fish sperm cryopreservation.

Ameliorative effect of grapefruit juice on amiodarone-induced cytogenetic and testicular damage in albino rats

OBJECTIVE

To evaluate the ameliorative role of grapefruit juice on the cytogenetic and testicular damage induced by the antiarrythmic drug amiodarone in albino rats.

METHODS

Animals were divided into four groups. Group I was considered as control. Group II was given grapefruit juice at a dose level of 27 mL/kg body weight. Group III was orally administered amiodarone (18 mg/kg body weight) daily for 5 weeks. Animals were sacrificed after 5 weeks of treatment. Bone marrow was collected from the femurs for analysis of chromosomal aberrations and mitotic indices. Testes were removed and stained with H&E for histological examination. Sperms were collected from epidedymis for detection of sperm head abnormalities. Comet assay was used to detect DNA damage.

RESULTS

Amiodarone treatment caused a significant increase in the percentage of chromosomal aberrations, decreased the mitotic index and increased DNA damage. The testis showed many histopathological alterations, inhibition of spermatogenesis and morphometric changes. The number of sperm head abnormalities was increased. Treating animals with amiodarone and grapefruit juice caused a reduction in chromosomal aberrations, mitotic index, DNA damage and testicular alterations caused by amiodarone.

CONCLUSIONS

The results of this study indicated that grapefruit juice ameliorates the cytotoxicty and testicular alterations induced by amiodarone in albino rats and this is may be due to the potent antioxidant effects of its components.

Cypermethrin induced reproductive toxicity in male Wistar rats: protective role of Tribulus terrestris

The present study was designed to investigate role of ethanolic extract of Tribulus terrestris (EETT) against alpha-cypermethrin induced reproductive toxicity in male Wistar rats. 24 male Wistar rats weighing about 250-300g were divided in four groups. Group-I was control. alpha-cypermethrin (3.38 mg kg-1b.wt.) was given to group-IlI for 28 days. In Group-Ill, alpha-cypermethrin and EETT (100 mg kg -1b.wt.) were administered in combination for 28 days. Rats in group-IV were given EETT for 28 days. At the end of the experiment, rats were sacrificed, testes and epididymis were removed and sperm characteristics, sex hormones and various biochemical parameters were studied. Decrease in weight of testes and epididymis, testicular sperm head count, sperm motility, live sperm count, serum testosterone (T), follicle stimulating hormone (FSH), leutinizing hormone (LH), catalase (CAT), superoxide dismutase (SOD), glutathione S transferase (GST), glutathione reductase (GR), glutathione peroxidase (GPx), total protein content and increase in sperm abnormalities and lipid peroxidation (LPO) level was observed in rats exposed to cypermethrin. In combination group-Ill, EETT treatment ameliorated alpha-cypermethrin induced damage. EETT treatment in group-IV increased testes and epididymis weight, sperm head counts, sperm motility, live sperm counts, testosterone, FSH, LH, GSH, CAT, SOD, GST, GR, GPx and total protein content. The study suggested that Tribulus terrestris plant possess reproductive system enhancement and antioxidant activity.

Intercellular adhesion molecule-2 is involved in apical ectoplasmic specialization dynamics during spermatogenesis in the rat

In this study, we investigated the role of intercellular adhesion molecule-2 (ICAM2) in the testis. ICAM2 is a cell adhesion protein having important roles in cell migration, especially during inflammation when leukocytes cross the endothelium. Herein, we showed ICAM2 to be expressed by germ and Sertoli cells in the rat testis. When a monospecific antibody was used for immunolocalization experiments, ICAM2 was found to surround the heads of elongating/elongated spermatids in all stages of the seminiferous epithelial cycle. To determine whether ICAM2 is a constituent of apical ectoplasmic specialization (ES), co-immunoprecipitation and dual immunofluorescence staining were performed. Interestingly, ICAM2 was found to associate with β1-integrin, nectin-3, afadin, Src, proline-rich tyrosine kinase 2, annexin II, and actin. Following CdCl₂ treatment, ICAM2 was found to be upregulated during restructuring of the seminiferous epithelium, with round spermatids becoming increasingly immunoreactive for ICAM2 by 6-16 h. Interestingly, there was a loss in the binding of ICAM2 to actin during CdCl₂-induced germ cell loss, suggesting that a loss of ICAM2-actin interactions might have facilitated junction restructuring. Taken collectively, these results illustrate that ICAM2 plays an important role in apical ES dynamics during spermatogenesis.

Dose-response effects of estrogenic mycotoxins (zearalenone, alpha- and beta-zearalenol) on motility, hyperactivation and the acrosome reaction of stallion sperm

BACKGROUND

The aim of this study was to investigate the in vitro effects of the Fusarium fungus-derived mycotoxin, zearalenone and its derivatives alpha-zearalenol and beta-zearalenol on motility parameters and the acrosome reaction of stallion sperm. Since the toxic effects of zearalenone and its derivatives are thought to result from their structural similarity to 17beta-estradiol, 17beta-estradiol was used as a positive control for 'estrogen-like' effects.

METHODS

Stallion spermatozoa were exposed in vitro to zearalenone, alpha-zearalenol, beta-zearalenol or 17beta-estradiol at concentrations ranging from 1 pM - 0.1 mM. After 2 hours exposure, motility parameters were evaluated by computer-assisted analysis, and acrosome integrity was examined by flow cytometry after staining with fluoroscein-conjugated peanut agglutinin.

RESULTS

Mycotoxins affected sperm parameters only at the highest concentration tested (0.1 mM) after 2 hours exposure. In this respect, all of the compounds reduced the average path velocity, but only alpha-zearalenol reduced percentages of motile and progressively motile sperm. Induction of motility patterns consistent with hyperactivation was stimulated according to the following rank of potency: alpha-zearalenol > 17beta-estradiol > zearalenone = beta-zearalenol. The hyperactivity-associated changes observed included reductions in straight-line velocity and linearity of movement, and an increase in the amplitude of lateral head displacement, while curvilinear velocity was unchanged. In addition, whereas alpha- and beta- zearalenol increased the percentages of live acrosome-reacted sperm, zearalenone and 17beta-estradiol had no apparent effect on acrosome status. In short, alpha-zearalenol inhibited normal sperm motility, but stimulated hyperactive motility in the remaining motile cells and simultaneously induced the acrosome reaction. Beta-zearalenol induced the acrosome reaction without altering motility. Conversely, zearalenone and 17beta-estradiol did not induce the acrosome reaction but induced hyperactive motility albeit to a different extent.

CONCLUSIONS

Apparently, the mycotoxin zearalenone has 17beta-estradiol-like estrogenic activity that enables it to induce hyperactivated motility of equine sperm cells, whereas the zearalenol derivatives induce premature completion of the acrosome reaction and thereby adversely affect stallion sperm physiology. The alpha form of zearalenol still possessed the estrogenic ability to induce hyperactivated motility, whereas its beta stereo-isomere had lost this property.

Developmental toxicity in mice following paternal exposure to Di-N-butyl-phthalate (DBP)

OBJECTIVE

The aim of the present study was to investigate the effects of paternal Di-N-butyl-phthalate (DBP) exposure pre- and postnatally on F1 generation offspring, and prenatally on F2 generation offspring.

METHODS

Male mice were exposed to either 500 mg/kg or 2 000 mg/kg of DBP for 8 weeks, and mated with non-exposed females. Three-quarters of the females were sacrificed a day prior to parturition, and examined for the number of living and dead implantations, and incidence of gross malformations. Pups from the remaining females were assessed for developmental markers, growth parameters, as well as sperm quantity and quality.

RESULTS

There were no changes in the fertility of parents and in intrauterine development of the offspring. Pups of DBP-exposed males demonstrated growth-retardation. Following paternal exposure to 500 mg/kg bw of DBP, there were almost twice the number of males than females born in the F1 generation. F1 generation females had a 2.5-day delay in vaginal opening. Paternal exposure to 2 000 mg/kg bw of DBP increased the incidence of sperm head malformations in F1 generation males; however, there were no changes in the fertility and viability of foetuses in the F2 generation.

CONCLUSION

Paternal DBP exposure may disturb the sex ratio of the offspring, delay female sexual maturation, and deteriorate the sperm quality of F1 generation males.

[Biological effects of phytoecdysteroids and chronic low-dose irradiation]

The influence of serpistene in dose of 5 and 50 mg/kg on chronic low-dose gamma-irradiation (22.6 cGy) effects on cytogenetic (abnormal sperm cell, marrow bone micronucleus) and function and morphology (thyroid and adrenal glands) parameters of mice was estimated. The serpistene modifies effects of gamma-irradiation depends on the administration regime and a dose of the substance. The most expressive radioprotective effect on endocrine organs after serpistene prophylactic administration was found. The prophylactic dose was 5 mg/kg for adrenal gland and both doses--for thyroid gland. The most expressive radioprotective effect on marrow bone cells after serpistene therapeutic administration in a dose of 5 mg/kg was found. The most expressive antimutagenic effect on somatic and germinal cells of prophylactic and therapeutic administration in a dose of 50 mg/kg was found.

Trypsin is a multifunctional factor in spermatogenesis

Trypsin is well known as a pancreatic enzyme that is typically secreted into the intestine to digest proteins. We show in our current study, however, that trypsin is also a key factor in the control of spermatogenesis. A progestin in teleost fish, 17alpha, 20beta-dihydroxy-4-pregnen-3-one (DHP), is an essential component of the spermatogenesis pathway, particularly during the initiation of the first meiotic division. In the course of our investigations into the mechanisms underlying progestin-stimulated spermatogenesis, we identified that eel trypsinogen is upregulated in eel testis by DHP treatment. Trypsinogen is expressed in the Sertoli cells surrounding spermatogonia and in the membranes of spermatids and spermatozoa. Using an in vitro eel testicular culture system, we further analyzed the roles of trypsin in spermatogenesis. The inhibition of trypsin using specific antibodies or serine protease inhibitors was found to compromise DHP-induced spermatogenesis. A low dose of trypsin induces DNA synthesis and the expression of Spo11, a molecular marker of meiosis, in germ cells. By comparison, a higher dose of trypsin partially induced spermiogenesis. Furthermore, trypsin was detectable in the membranes of the spermatozoa and found to be associated with fertilization in fish. Our results thus demonstrate that trypsin and/or a trypsin-like protease is an essential and multifunctional factor in spermatogenesis.

How to Increase the Motility of Spermatozoa from the Epididymis of Bulls and Alloplastic Spermatoceles in Minipigs

The motility of spermatozoa from the head and tail of the epididymis in bulls was studied. Qualitatively and quantitatively, the motility of spermatozoa from the cauda was distinctly better than that from the caput. It was possible to achieve a highly significant increase in the motility of epididymal spermatozoa from the caput as well as the cauda area using caffeine or a caffeine-kallikrein mixture. Above all, motility stimulants improved the local motility of the epididymal spermatozoa as compared to twitching and progressive motility. The motility of caudal spermatozoa was increased by 100%, corresponding to local movement of 59% of the total number of sperm cells. It was possible to demonstrate an increase in the almost totally absent motility of the caput spermatozoa to 27% local motility. Application of kallikrein without addition of kininogens led to no significant change in spermatozoa motility. By the addition of caffeine, it was possible to increase the motility of minipig epididymal spermatozoa taken by puncture from alloplastic spermatoceles significantly. In 23 aspirates, a prompt increase in the percentage of locally motile "spermatocele spermatozoa" from 12% to 23.5% was observed.

Protective effect of minocycline on dexamethasone induced testicular germ cell apoptosis in mice

BACKGROUND

Apoptosis involves in testicular germ cell loss in animals and humans, and plays an important role in male fertility. Previous studies have reported neuroprotective and antiapoptotic effects of minocycline.

AIM

In this study the protective effect of Minocycline on testicular germ cell apoptosis arising from dexamethasone (Dex) has been evaluated. Dex is a widely used as a glucocorticoid (GC) agent that its apoptotic effect has been shown.

MATERIALS AND METHODS

Experimental groups of 8 male mice received one of the following treatments daily for 7 days: 100 mg/kg Minocycline, 7 mg/kg Dex and 7 mg/kg Dex +100 mg/kg Minocycline. Control group was treated with 0.5 ml saline given orally for a week. Then the mice were sacrificed, and their testes processed for assessment of germ cell apoptosis (TUNEL method), the quality of spermatogenesis (Johnsen score system) and testicular sperm counts.

RESULTS

Germ cell apoptosis were significantly increased in Dex treated mice compared with control (P < 0.01). Spermatogenesis and the number of sperms head were significantly reduced in Dex treated mice compared with those of the control group (P < 0.01). Treatment with Dex and Minocycline resulted in an inhibition effect on germ cell apoptosis and a significant increase in the Johnsen score and the number of head sperm compared with Dex treated mice (P < 0.05).

CONCLUSION

The application of Minocycline may serve as a beneficial medication to protect germ cells against apoptosis.

Effects of low dose radiation and vitamin C treatment on chloroquine-induced genotoxicity in mice

Chloroquine (CHQ) is a commonly used antimalarial agent. We evaluated the genotoxic potential of CHQ using chromosome aberration (CA), micronucleus (MN), and sperm head abnormality (SA) assays in vivo in Swiss albino mice. The interaction between a low dose of radiation and CHQ, as well as the effect of vitamin C on CHQ-induced genotoxicity, was also evaluated. It was observed that CHQ induced CA, as well as MN, in the bone marrow cells under certain treatment conditions. Further, CHQ induced significant increase in the frequency of SA both at 24 hr and 21 days of the treatment. In the present study vitamin C pretreatment apparently reduced the frequency of CA, MN, and SA induced by CHQ. In the combination studies with radiation and CHQ, we found that exposure to low doses of radiation (0.5 Gy) either prior to or following CHQ treatment, in the dose ranges tested, has little or no synergistic effect in the mutagenic evaluations in somatic cells. However, radiation exposure along with CHQ treatment resulted in significant increase in the frequency of SA as compared to the groups receiving CHQ alone at 21 days of the treatment. In summary, CHQ has the potential to induce genotoxicity in mammalian cells. Further, germ cells may be relatively more sensitive as compared to the somatic cells.

A comparison of the protective action of added egg yolks from five avian species to the cryopreservation of bull sperm

Cryopreservation of domestic animal sperm has been widely used for artificial insemination (AI), and egg yolk is one of the most commonly used cryoprotectants during the freezing-thawing process. The objectives of this study were to compare the effectiveness of egg yolk from five avian species (domestic chicken, domestic duck, domestic goose, Japanese quail or domestic pigeon) and to optimize the concentration of egg yolk on the cryopreservation of bull sperm in terms of frozen-thawed sperm progressive motility and viability. The results were two-fold. First, they showed that pigeon egg yolk provided the best cryoprotective effects on the cryopreservation of bull sperm, compared with egg yolk of chicken, quail, goose or duck. Second, the best concentration of pigeon egg yolk in extender was 20% during cryopreservation among five concentrations of 5, 10, 20, 30 or 40%. The results suggest that pigeon egg yolk could be used as an alternative to chicken egg yolk in extender but requires further testing in fertility trials.

Efficacy of a plant extract (Chelidonium majus L.) in combating induced hepatocarcinogenesis in mice

Ethanolic whole plant extract of Chelidonium majus, extensively used in traditional systems of medicine against various liver ailments, has been tested for its possible anti-tumor, hepato-protective and anti-genotoxic effects in p-dimethylaminoazobenzene (p-DAB) induced hepatocarcinogenesis in mice through multiple assays: cytogenetical, biochemical, histological and electron microscopical. Different sets of mice, 5 (for 7, 15 and 30 days' treatment) or 10 (for 60, 90 and 120 days) each, were chronically fed a diet suitably mixed with p-DAB and phenobarbital to develop liver tumors. One sub-group of carcinogen fed mice was also fed C. majus extract; 0.1 ml daily (drug-treated) while the other equal amount of dilute ethyl alcohol ("vehicle" of plant extract) (positive control). A separate group of mice was maintained with normal diet without any carcinogen treatment (negative control). Data of several cytogenetical endpoints and biochemical assay of some toxicity marker enzymes at all fixation intervals and histology of liver sections through ordinary, scanning and transmission electron microscopy at 60 and 120 days and that of spleen and kidney at 90 days were critically analyzed in the treated lots vis-a-vis controls. The results suggest anti-tumor, anti-genotoxic and hepato-protective effects of the plant extract, showing potentials for use in cancer therapy.

Protective role of ascorbic acid on subacute sperm toxicity in male New Zealand white rabbits treated with endosulfan

The ameliorating effect of oral ascorbic acid (AA) was evaluated against changes in sperm parameters in New Zealand White (NZW) rabbits treated with endosulfan. Rabbits (6 to 8 months old) were divided into four groups of six animals each. Rabbits in TRT-I served as control and received corn oil by oral gavage for 6 weeks. Rabbits in TRT-II received endosulfan (1 mg/kg bw per day) in corn oil. TRT-III group received oral corn oil daily and ascorbic acid (AA; 20 mg/kg bw) every other day for 6 weeks. TRT-IV group received the same amounts of endosulfan and AA. Endosulfan alone significantly reduced the sperm count and motility and increased the presence of sperm with morphologic problems. AA treatment showed significant amelioration when coupled with endosulfan. Ameliorations were up to control levels in all cases except for sperm motility. The data suggested that AA has beneficial influences in neutralizing the toxic effects of endosulfan in the spermatologic parameters of NZW males.

The effects of carbamazepine on sperm morphology in wistar rats

Carbamazepine (5 H-dibenz (b, f) azepine-5-carboxamide), is an antiepileptic drug which is expected to be administered regularly over a substantial part of patients lifetime. As the gender focus in epilepsy the later years has primarily been on women, there certainly is a lack of studies focused on the effects particular to men. The present study was aimed to investigate its effects on germ cell's by employing the sperm morphology assay. Twelve groups of male wistar rats were treated with sterile water 0.5 ml, cyclophosphamide (CP) 20 mg/kg, carbamazepine 9, 18, 36 mg/kg (i.p) and 2% gumacasia 0.25 ml/100 g respectively for 5 consecutive days at intervals of 24 hrs. Following the last exposure, on days 14 and 35 sperm morphology assay was conducted as per the standard procedure. Mann-Whitney 'U' test was used for statistical analysis and the level of significance was P<0.01. Neither carbamazepine nor cyclophosphamide induced formation of abnormally shaped sperms at 14 day time interval. Whereas on day 35, with 18 mg/kg dose level of carbamazepine there was an increase in the number of sperms with heads defects (P<0.01); Whereas in the other two dose levels the number of abnormally shaped sperms had decreased. 2% gumacasia increased the number of sperms with tail defects at day 35. (Mann-Whitney 'U' test).

CONCLUSION

Carbamazepine and 2% gumacasia could be germ cell mutagens and could cause infertility on prolonged use therefore further studies with serum drug level estimations are needed.

Localization and regulation of plasma membrane Ca2+-ATPase in bovine spermatozoa

Calcium (Ca(2+)) signals, produced by the opening of plasma membrane entry channels, regulate a number of functions in spermatozoa such as capacitation and motility. The mechanisms of Ca(2+) removal from the sperm, required to restore resting [Ca(2+)](i), include plasma membrane Ca(2+)-dependent ATPase (PMCA) isoenzymes as well as a plasma membrane Na(+)-Ca(2+) exchanger. We have recently shown that bovine sperm PMCA is stimulated by PDC-109, a secretory protein of bovine seminal vesicles. To demonstrate the subcellular localization and regulation of bovine sperm PMCA, we have performed cell fractionation, enzyme activity determination and Western blotting studies of PMCA in spermatozoa removed from the cauda epididymidis of bull. Fractionation of sperm heads and tails resulted in a distinct association of ATPase activity with the tail membrane fraction. In vitro stimulation studies with PDC-109 using intact and fractionated sperm showed an increase in enzyme activity up to 105% in sperm tail membranes. Furthermore, thapsigargin inhibition did not alter the stimulatory effect of PDC-109 on ATPase activity, indicating that no sarco/endoplasmic reticulum Ca(2+)-ATPase (SERCA), but only PMCA isoenzymes are involved in this effect. Western blotting studies using a polyvalent PMCA antibody showed the exclusive presence of a 135 kDa band in the tail plasma membrane fraction. To elucidate whether or not the stimulatory effect was a direct one or indirectly mediated through PKA and PKC activation, PKA and PKC inhibitors, respectively, were used in the Ca(2+)-ATPase activity assays, which was followed by PDC-109 stimulation. The stimulatory effect of PDC-109 on PMCA was still observed under these conditions, while no phosphotyrosine proteins could be detected by Western blotting in sperm extracts following PDC-109 treatment. Co-immunoprecipitation studies, PDC-109 affinity chromatography as well as overlay blots failed to show a strong association of both PMCA and PDC-109, pointing to an indirect, perhaps phospholipid-mediated effect.

An in vivo evaluation of the induction of abnormal sperm morphology by sulphamethoxypyridazine: pyrimethamine (Metakelfin)

The effects of sulphamethoxypyridazine: Pyrimethamine (Metakelfin) a combination antimalarial drug on mouse sperm head morphology were evaluated in University of Ibadan Veterinary F1 mice. Five different dose levels of 3.85:0.19; 7.7:0.38; 15.4:0.76; 23.1:1.13 and 30.8:1.54 mg kg(-1) body weight of sulphamethoxypridazine:pyrimetamine, respectively were administered to the animals by a schedule of 5 consecutive daily intraperitoneal (i.p.) injections. The sperm of the mice from the cauda epididymis were examined 5 weeks after treatment. Metakelfin induced sperm head abnormalities; however, of the 5 doses sampled; only the 7.7:0.38 mg kg(-1) dose, corresponding to 0.5x the human therapeutic dose (HTD0), gave a statistically significant (p > 0.05) increase over the negative control value of 2.53% abnormality. All the other dose level treatments did not yield statistically significant increase over the negative control value. The 15.4:0.77 mg kg(-1) dose showed 3.5% abnormality and fewer abnormalities than the preceding lower dose. The drug is probably not mutagenic as induction of sperm head abnormality was not dose dependent.

Beneficial effects of vitamin E in sperm functions in the rat after spinal cord injury

Male infertility as a result of spinal cord injury (SCI) is associated with abnormal semen qualities including low sperm counts and poor sperm motility and morphology. Clinical studies suggest that reactive oxygen species (ROS)-related events might contribute to abnormal sperm functions after SCI. The current study examined whether impaired sperm functions after SCI can be ameliorated by an antioxidant, vitamin E. Vitamin E feeding of spinal cord transected (SCX) rats during the acute (maintenance) and chronic (restoration) phases of the injury partially preserved sperm viability and mitochondrial potential; similar effects were only seen in spinal cord contused (SCC) rats during the chronic phase. A beneficial effect of vitamin E on sperm motility, however, was only observed in SCX rats during the chronic phase of the injury. These results suggest that ROS-related events might account for some of the effects of cord injury on sperm functions, depending on the extent of injury and time postinjury. Furthermore, we found that sperm heads from SCC and SCX rats were less condensed compared to those from sham control rats. Such effects were attenuated by vitamin E, suggesting that ROS-related events may also contribute to abnormal sperm morphology after SCI. Partial restoration of male accessory gland weights in those rats fed vitamin E further suggests its beneficial effects on the functions of these glands.

CONCLUSION

Vitamin E feeding attenuated some of the effects of spinal cord injury on sperm functions and male accessory glands in the rat. These results support a role of ROS-related events in deterioration of semen quality after cord injury. Further understanding of the underlying mechanisms for effects of vitamin E on sperm functions and male accessory glands will provide scientific rationale for the use of vitamin E or other antioxidant as therapeutic means to preserve sperm functions and semen quality in SCI men.

Chenopodium album seed extract: a potent sperm-immobilizing agent both in vitro and in vivo

PURPOSE

Aqueous decoction of Chenopodium album seeds (CAD) was assessed for its sperm-immobilizing and contraceptive efficacy in laboratory mammals.

METHOD

Spermicidal efficacy was evaluated in vitro by a modified Sander-Cramer test. The mode of spermicidal action was assessed by (a) supravital and double fluoroprobe staining of sperm, (b) hypoosmotic swelling tests and (c) transmission electron microscopy. Contraceptive efficacy was evaluated by intrauterine and vaginal application of CAD in rats and rabbits, respectively, followed by their mating and evaluation of pregnancy outcomes.

RESULTS

The minimum effective concentration of CAD that induced instantaneous immobilization of rat spermatozoa in vitro was 2 mg/mL. The mechanism of CAD action involved disintegration of sperm plasma membrane and dissolution of acrosomal cap causing sperm death. Fertilization of oocytes and establishment of implantation were prevented in the uterine horn that was administered with CAD, while these events occurred unhindered in the untreated contralateral side. In rabbit, intravaginal application of CAD significantly blocked the establishment of pregnancy.

CONCLUSION

CAD possesses appreciable spermicidal potential, which may be explored as an effector constituent of vaginal contraceptive.

Adduction of biomacromolecules with acrylamide (AA) in mice at environmental dose levels studied by accelerator mass spectrometry

Since 2002, WHO has strongly called scientists to investigate intensively the toxicity and potential carcinogenicity of acrylamide (AA), because humans are widely exposed to AA via various foodstuffs. In this study we measured the biomacromolecule adducts of [2,3-(14)C]AA (0, 7.5 x 10(-2), 7.5 x 10(-1), 7.5, 9.3 x 10(1), 2.4 x 10(2) and 1.0 x 10(3)microg/kg b.w.) in adult male mice by ultrasensitive accelerator mass spectrometry (AMS) technique. The aim is to evaluate the potential molecular toxicity of AA at human relevant dose levels, particularly towards the sperm cells. Hemoglobin (Hb), serum albumin (SA), protamine, sperm DNA, tails and heads were isolated 24h post dosing and the adduct levels were measured by AMS, respectively. Good log/log linear dose-response correlations were established. Moreover, the correlation of AA-protamine adducts, AA-sperm DNA adducts, as well as AA-sperm head/tail adducts with AA-Hb or AA-SA adducts presented a linear log/log mode. In sperm, the formation of AA-protamine adducts were predominating to AA-DNA adducts. The adducts on sperm heads/tails might both influence the fertility efficacy.

Intracytoplasmic sperm injection in the bovine induces abnormal [Ca2+]i responses and oocyte activation

Fertilisation by intracytoplasmic sperm injection (ICSI), a technique that bypasses the membrane fusion of the gametes, has been widely used to produce offspring in humans and mice. Success with this technique has lent support to the hypothesis that in mammalian fertilisation, a factor from the sperm, the so-called sperm factor, is responsible for oocyte activation and that the fusion process is not involved in the generation of the hallmark [Ca2+]i signalling seen following fertilisation. However, the success of ICSI has largely eluded large domestic species, such as the bovine, porcine and equine, casting doubt on the current model of oocyte activation at fertilisation in these species. Using Ca2+ imagery and a series of treatments to manipulate the chemical structure of the sperm, we have investigated the early events of oocyte activation in response to ICSI in the bovine. Our results demonstrate, for the first time, that following ICSI, the majority of bovine oocytes are unable to mount [Ca2+]i oscillations, although, in few cases, the initiation of [Ca2+]i oscillations can occur in a manner indistinguishable from in vitro fertilisation. We also show that bull sperm possess a full complement of sperm factor. However, either the release and/or activation of the sperm factor are compromised after ICSI, leading to the delivery of a defective Ca2+ stimulus, which results in premature termination of embryo development.

Protective potentials of a potentized homeopathic drug, Lycopodium-30, in ameliorating azo dye induced hepatocarcinogenesis in mice

The protective potentials of a potentized homeopathic drug, Lycopodium-30, prepared from extract of spores of a plant, Lyocopodium clavatum (Fam: Lycopodiaceae) and used as a remedy for various liver ailments, have been tested in mice chronically fed p-dimethyl amino azo benzene (p-DAB) - an initiator, and phenobarbital (PB) - a promoter of hepatic cancer, by using some cytogenetic endpoints like chromosome aberrations (CA), micronuclei (MN), mitotic index (MI) and sperm head abnormality (SHA), and toxicity biomarkers like acid and alkaline phosphatases (AcP and AlkP, respectively), alanine and aspartate amino transferases (ALT and AST, respectively) and lipid peroxidation (LPO) and reduced glutathione (GSH) activities. The effects of chronic treatment of the carcinogens were assessed at different intervals of fixation, namely, at day 7, 15, 30, 60, 90 and day 120, and compared with that of mice fed conjointly with the carcinogens and the homeopathic remedy. Both the assay systems indicated considerable protective potentials of the homeopathic remedy against p-DAB induced hepatocarcinogenesis in mice.

Topological alterations in human spermatozoa associated with the polyelectrolytic effect of RISUG

A new method of male contraception has been developed which results in long-term infertility and has the potential advantage of being reversible. The contraceptive, given the name RISUG (an acronym for Reversible Inhibition of Sperm Under Guidance) is a polyelectrolytic compound and when injected into the lumen of the vas deferens, induces a surface charge imbalance on the sperm membrane system leading to its destabilization. In the present study, morphological and topological alterations in human spermatozoa induced by RISUG have been investigated using atomic force microscopy (AFM). Complete disintegration of the plasma membrane with subsequent rupture and dispersion of the acrosomal contents is observed on treatment with RISUG in vitro. Considerable damage to the midpiece region with significant clustering of the mitochondria and its fusion with the head region is also observed. These observations are in agreement with the significant increase in the volume of RISUG-treated sperm-head region. Topological alterations in the flagellar and midpiece region of RISUG-treated spermatozoa have also been studied.

In vivo evaluation of induction of abnormal sperm morphology in mice by an unsaturated aldehyde crotonaldehyde

Crotonaldehyde, a highly reactive unsaturated aldehyde is used for the manufacture of sorbic acid, synthesis of butyl alcohol, butylaldehyde, quinaldine, thiophenes, pyridines, dyes, pesticides, pharmaceuticals, rubber antioxidants, chemical warfare agents, etc. and also occurs naturally in meat, fish, in many fruits and vegetables, bread, cheese, milk, beer, wine and liquors. Human exposure to crotonaldehyde occurs from both man-made and natural sources. No human data was located describing carcinogenicity associated with crotonaldehyde exposure. In the present study we have evaluated whether or not exposure to crotonaldehyde results in a significant increase in the frequency of abnormal sperm heads in male Swiss albino mice. Adult male mice were treated with 8, 16 and 32 microl/kg b.w. of crotonaldehyde as a single intraperitoneal injection. The animals were killed 1, 3 and 5 weeks after treatment. Five animals were sacrificed per dose and time tested. Crotonaldehyde induced dose related increase in the percentage of abnormal sperm heads. Statistically significant increase in percentage of abnormal sperm heads was recoded at 16 and 32 microl/kg b.w. after 1 and 3 weeks of treatment and only at 32 microl/kg b.w. after 5 weeks of treatment.

Plasma membrane calcium ATPase is concentrated in the head of sea urchin spermatozoa

Plasma membrane Ca2+ATPases (PMCAs) export Ca2+ from cells in a highly regulated manner, providing fine-tuning to the maintenance of intracellular Ca2+ concentrations. There are few studies of PMCAs in spermatozoa, which is surprising considering the importance of this enzyme in all cell types. Here we describe the primary structure and localization of the PMCA of sea urchin spermatozoa (suPMCA). The suPMCA is 1,154 amino acids and has 56% identity and 76% similarity to all 4 human PMCA isoforms. The suPMCA shares the features of a typical PMCA, including domains for calmodulin binding, ATP binding, ATPase phosphorylation, and 10 putative transmembrane segments with two large cytoplasmic loops. Southern blots show that suPMCA is a single copy gene. Treatment of live sea urchin sperm with the PMCA inhibitor, 5-(-6)-carboxyeosin, results in elevations of intracellular Ca2+ and loss of flagellar motility. Immunoblotting and immunoflorescence show that suPMCA is concentrated in the sperm head plasma membrane. In previous work, we showed that a plasma membrane K+ dependent Na+/Ca2+ exchanger (suNCKX), which also keeps Ca2+ low in these cells, is concentrated in the sperm flagellum. Thus, the sperm head and flagellum localize different gene products, both functioning to keep intracellular Ca2+ low, while the sperm swims in seawater containing 10 mM Ca2+.

Genotoxic consequences associated with oxidative damage in testis of mice subjected to iron intoxication

While iron-induced testicular dysfunction has been demonstrated adequately, the mechanism(s) involved and the genotoxic implications are not fully understood. In order to understand the genotoxic effects of iron intoxication, initially induction of oxidative stress response in testis of adult albino mice (CFT-Swiss) was ascertained following administration (i.p.) of acute sub-lethal doses of iron dextran (ID). Subsequently, multiple sub-lethal doses (50, 100 and 200 mg/kg bw/day) were employed to characterize effects on lipid peroxidation (LPO) in testis (homogenates, microsomal/mitochondrial fractions), DNA damage and incidence of abnormal sperms. While acute doses of ID induced only a marginal increase in LPO response in testis at 24 h of administration, multiple doses elicited a moderate (30-40%) increase in LPO in whole homogenates and significant dose-related elevation in both mitochondrial (20-45%) and microsomal fractions (25-65%). This was associated with significant increase in DNA damage in the testis as evidenced by increased single strand breaks in a fluorimetric analysis of DNA unwinding (FADU) assay. Further, evidences of oxidative damage in testis was evident in terms of increased protein carbonyls and altered antioxidant enzymic activities. The genotoxic implications were investigated by quantification of the frequency of abnormal sperms sampled at specific periods during spermatogenetic cycle. Nearly three- to seven-fold increase in percent abnormal sperms among the ID treated males were evident during the first 3 weeks although the counts were unaffected. Interestingly, in a classical dominant lethal (DL) assay, mating of ID treated (100 mg/kg bw/day for 5 days) males sequentially for a period of 5 weeks with untreated females resulted in a significant increase in male-mediated dominant lethal type mutations (the frequency of dead implants) during the first 3 weeks only indicating a stage-specific effect on post-meiotic germ cells. These findings provide an account of the early oxidative damage in testis in vivo following exposure to low levels of iron which may be wholly or in part responsible for the genotoxic consequences observed in this model of iron overload.

An in vivo evaluation of induction of abnormal sperm morphology in mice by landfill leachates

Although several reports have demonstrated the acutely toxic and genotoxic effects of landfill leachates in microbial organisms, plants and aquatic animals, the effects of pollutants present in these leachates have not been clarified yet in terrestrial animals. This study mainly aimed to evaluate a potential genetic effect of raw and simulated leachates from Orita-Aperin and Oworonsoki landfills in south-west Nigeria by use of the murine sperm-head abnormality test. These landfills neither have a synthetic membrane liner at the bottom, nor a natural layer of compacted soil with the desired hydraulic conductivity, nor a run-off control system. As a result, the leachates produced are discharged into the environment. Samples designated as Orita-Aperin Raw Leachate (OARL), Orita-Aperin Simulated Leachate (OASL), Oworonsoki Raw Leachate (OWRL) and Oworonsoki Simulated Leachate (OWSL) were analyzed in the sperm-head abnormality test at concentrations (v/v) of 1%, 2.5%, 5%, 10% and 25%. Mice were given 0.5 ml sample per day for five consecutive days by intraperitoneal injection. Each dose group comprised seven mice, and a 5-week exposure period was utilized. The data show that the test mixtures induced a dose-dependent, statistically significant increase (P<0.05) in the number of sperm with abnormal morphology. Physico-chemical analysis of the test samples shows that they contained constituents that are capable of inducing mutation in biologic system. The interaction of some of these constituents with the genetic material in the differentiating cells during spermatogenesis may be responsible for these observations. This is relevant in environmental waste management, and for the assessment of the hazardous effects of the chemicals in landfill leachates.

Assessment of the genotoxic and cytotoxic potential of an anti-epileptic drug, phenobarbital, in mice: a time course study

To examine if chronic oral administration of phenobarbital (PB), a widely used anti-epileptic drug, has any genotoxic and cytotoxic potential in mice, a mammalian model, cytogenetic assays through several endpoints such as chromosome aberrations, induction of micronuclei, mitotic index of bone marrow cells, sperm-head anomaly in testis and enzymatic assays of several toxicity marker enzymes have been conducted by use of standard techniques. Mice of both treated (chronically receiving an oral dose of PB at 1.2 mg/kg bw) and control (without receiving PB) groups were sacrificed at 7, 15, 30, 60, 90 and 120 days for the study with all the above-mentioned protocols. Further, total protein profiles in liver of both control and treated mice were analyzed through the SDS-PAGE technique at day 60. The results of all these studies, when compared with controls, showed that PB has both genotoxic and cytotoxic potential in apparently increasing intensity at longer periods of chronic feeding in mice, which would warrant due consideration in its long-term use on human subjects.

Adult 2,3,7,8-Tetrachlorodibenzo-p-Dioxin (TCDD) Exposure and Effects on Male Reproductive Organs in Three Differentially TCDD-Susceptible Rat Lines

The contribution of genetic factors to adult male reproductive system toxicity of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) was analyzed in three rat lines differentially resistant to TCDD acute lethality: line A, B, and C rats (selectively bred from TCDD-resistant Han/Wistar [Kuopio; H/W] and TCDD-sensitive Long-Evans [Turku/AB; L-E] rats). The resistance is linked to a mutated H/W-type aryl hydrocarbon receptor allele in line A and to an H/W-type unknown "B" allele in line B. Line C rats do not have resistance alleles. Mature male line A, B and C rats were given single oral doses up to 1000, 300, and 30 micrograms/kg TCDD, respectively. The dose-responses of TCDD effects on male reproductive organ weights, sperm numbers, and serum testosterone concentrations were analyzed 17 days after exposure. Serum testosterone concentrations were decreased by the highest doses of TCDD, and there were no major sensitivity differences among the rat lines. Correspondingly, the decrease in relative weight of ventral prostate and seminal vesicles was seen only after a dose of >/=100 micrograms/kg TCDD. Thus the effect was observed only in resistant lines A and B. The relative weights of testes and epididymides were not affected. Significant decrease in spermatogenesis was observed in each rat line, but the amount of decrease was reduced by resistance alleles. The highest TCDD dose decreased the daily sperm production by 37, 38, and 60% in line A, B, and C rats, respectively. Therefore, the resistance alleles appear to selectively modify the TCDD effects on the adult male reproductive system. The fact that the influence of resistance alleles on spermatogenesis is different from that on androgenic status indicates that the effect of TCDD on sperm numbers is not fully related to decreased serum testosterone.

Genotoxic effects of cadmium chloride and azadirachtin treated singly and in combination in fish

The genotoxic effects of cadmium chloride (CdCl(2)) and azadirachtin (Aza) were assessed singly and conjointly in a fish, Oreochromis mossambicus, with endpoints such as chromosome aberrations, abnormal red cell nuclei, abnormal sperm morphology, and protein content (both qualitative and quantitative) of selected tissues, namely, muscle, heart, eye, brain, gill, liver, spleen, and kidney. The primary objectives were, first, to examine if CdCl(2), a common pollutant, and Aza, a natural product of the neem plant used extensively as an 'ecofriendly' agent for many purposes, had any genotoxic effect of their own on nontarget aquatic organisms of economic importance; and second, if Aza could have any ameliorating effect on CdCl(2)-induced genotoxicity in O. mossambicus tissues. As compared with distilled water-treated controls, both CdCl(2) and Aza induced genotoxicity in O. mossambicus, the former in greater quantity than that produced by Aza. However, Cd-induced toxicity in O. mossambicus appeared to be ameliorated to some extent by Aza.

Use of atomic force microscopy to reveal sperm ultrastructure in HIV-patients on highly active antiretroviral therapy

Atomic force microscopy (AFM) has been employed to examine morphological and topographical changes caused by human immunodeficiency virus (HIV) and the effects of highly active antiretroviral therapy (HAART) on spermatozoon of HIV infected patients. This powerful technique has allowed us to visualize morphological alterations present in the spermatozoa of patients either with or without treatment. In addition to this, even the minute details, such as viral particles, located on the membrane of the spermatozoa, and the merging of such particles on the surface of the spermatozoa were detected with precision. The most important aspect is that AFM, unlike electron microscopy, permits to image virions in their nearly natural environment. Excess of damage of spermatozoon is due to the chemicals involved in HAART rather than the damage made by virus.

Ameliorating effect of beta-carotene on ethylmethane sulphonate-induced genotoxicity in the fish Oreochromis mossambicus

Genotoxic effects have been assessed in the fish Oreochromis mossambicus treated separately and conjointly with 0.2% ethylmethane sulphonate (EMS) and 0.05% beta-carotene (BC) during five different time periods (6, 24, 48, 72 and 96 h) by analysis of endpoints such as chromosome aberrations, abnormal red blood cell nuclei, abnormal sperm morphology and protein contents (both qualitative and quantitative) of selected tissues, viz. muscle, heart, eye, brain, gill, liver, spleen and kidney. In addition, the relative efficacy of three doses of BC 0.02, 0.05 and 0.1%, in ameliorating genotoxic effects of 0.2% EMS was also tested after a treatment period of 48 h. EMS caused chromosomal aberrations, nuclear anomalies in red blood cells, abnormal sperm morphology and an apparent alteration of protein synthesis in various tissues. Some of these genotoxic effects of EMS appeared to be ameliorated by all three doses of BC, of which the 0.02% dose showed a marginally better efficacy.

Factors affecting fertilization of porcine oocytes following intracytoplasmic injection of sperm

The objective of this study was to optimize intracytoplasmic sperm injection (ICSI), and to assess the effects of membrane-damaged sperm on development of porcine oocytes following ICSI. For optimization of development following the ICSI process, sperm injected oocytes were activated 0.5-1.0 hr after ICSI with 1 x 30 micros pulse of 1.2, 1.7, 2.2, and 2.7 kV/cm DC in experiment 1. After 7-days of culture ICSI oocytes activated with [x1]2.2 kV/cm produced more blastocyts ([x2]34.4%, P < 0.05) than other treatment groups. In experiment 2, oocytes were activated with 1 x 30 micros pulse of 2.2 kV/cm at either 0, 1.5, 3, or 6 hr after ICSI. Oocytes activated 1.5 hr after [x3]ICSI yielded more blastocysts (27.6%)[M4] than in other treatments. In experiment 3, sperm were briefly exposed to 0.1% Triton X-100 to induce membrane damage. Live-dead staining of Percoll-sorted untreated spermatozoa (frozen-thawed) used in this study showed that over 96% were "alive" whereas none were "alive" after Triton X-100 treatment. The rate of development to blastocyst of oocytes injected with Triton X-100 treated sperm combined with electrical activation (EA) at 1 x 30 micros pulse of 2.2 kV/cm (EA, 40.0%) was the best, when compared with those injected with untreated sperm plus EA (P < 0.05). In experiment 4, the development rate of oocytes to the blastocyst stage ([x5]32.1%) following injection of a sperm head only was not significantly different from that of oocytes injected with whole sperm (31.0%). In conclusion, we found that an intact membrane and tail structures of pig spermatozoa are not essential for embryo development by ICSI, and furthermore, dead porcine spermatozoa, at an early stage of necrosis caused by plasma membrane damage, support better embryo development than do live non-damaged sperm.

Ultrastructural changes induced by leaves of Azadirachta indica (Neem) in the testis of albino rats

The present work was designed to study the effect of Azadirachta indica (Neem) powder on rat testis using the electron microscope. Male albino rats received 100 mg each A. indica leaf powder orally (by gavage). On alternate days, a second group of rats received 0.125 mg testosterone dipropionate intramuscularly. A third group received both A. indica leaf powder by gavage and testosterone dipropionate intramuscularly. Suitable controls were maintained. After autopsy, ultrastructural analysis of the testis revealed that animals treated with testosterone dipropionate showed well-developed Sertoli cells and germ cells with well-developed cytoplasmic organelles. By contrast, in A. indica-treated rats, intracellular spaces and vacuolization were observed in Sertoli cells; whereas in Leydig cells, cytoplasmic inclusions appeared diminished, and the configuration of granular endoplasmic reticulum appeared as a single unbranched tubule. In late spermatids, defects were observed in the mitochondrial sheath. The ultrastructural changes seen in the A. indica-treated group provide a clue that A. indica leaves might affect spermatogenesis through antispermatogenic and antiandrogenic properties.

Cytogenetic toxicity of neem

The cytogenetic toxicity of the leaf extract of neem was evaluated in murine germ cells. The extract was found to induce structural and numerical changes in the spermatocyte chromosomes as well as synaptic disturbances in them at their first metaphase. A significant increase in the frequency of sperms with abnormal head morphology and the decrease in mean sperm count were also observed. This spermatotoxic effect of the neem extract corroborates its germ cell mutagenicity. The possible role of azadirachtin, the most active principle present in the neem extract, in producing the observed genotoxic effect is discussed.

[The female pheromone 2,5-dimethylpyrazine induces sperm head abnormalities in male CBA mice]

The effect of the house mouse female pheromone 2,5-dimethylpyrazine (2,5-DMP) on sperm differentiation in male CBA mice has been studied. For this purpose, mature males were treated with a 0.01% aqueous solution of the pheromone for six days. Control mice were similarly treated with physiologic saline. The mice were sacrificed 23 days after the treatment, and material for the analysis of sperm-head abnormalities was sampled from the caudal portion of the epididymis. Analysis of the frequency of abnormal sperms has demonstrated that the pheromonal treatment significantly increases the frequencies of various sperm-head abnormalities. Apparently, this results from disturbances in sex-cell differentiation germline cells caused by the induction of genetic damage at stages immediately preceding meiosis, as well as during the first and second meiotic divisions. The relationship between the effect of 2,5-DMP and the decrease in the fertility of male CBA mice that was earlier observed after a similar treatment is discussed.

Caspase-independent exposure of aminophospholipids and tyrosine phosphorylation in bicarbonate responsive human sperm cells

Only capacitated sperm cells are able to fertilize egg cells, and this process is triggered by high levels of bicarbonate. Bicarbonate renders the plasma membrane more fluid, which is caused by protein kinase A (PKA)-mediated alterations in the phospholipid (PL) bilayer. We studied exposure of phosphatidylserine (PS) and phosphatidylethanolamine (PE) in human sperm cells. Surface exposure of PS and PE on sperm cell activation in vitro was found to be bicarbonate dependent and restricted to the apical area of the head plasma membrane. The PL scrambling in bicarbonate-triggered human sperm was not related to apoptosis, because the incubated cells did not show any signs of caspases or degeneration of mitochondria or DNA. The PL scramblase (PLSCR) gene family has been implicated in this nonspecific, bidirectional PL movement. A 25-kDa isoform of PLSCR was identified that was homogeneously distributed in human sperm cells. We propose that compartment-dependent activation of PKA is required for the surface exposure of aminophospholipids at the apical plasma membrane of sperm cells. Bicarbonate-induced PL scrambling appears to be an important event in the capacitation process, because the entire intact scrambling sperm subpopulation showed extensive tyrosine phosphorylation, which was absent in the nonscrambling subpopulation. The proportion of live cells with PL scrambling corresponded with that showing capacitation-specific chlortetracyclin staining.

Cisplatin-induced genotoxic effects and endogenous glutathione levels in mice bearing ascites Dalton's lymphoma

cis-Diaminedichloroplatinum(II), commonly known as cisplatin, treatment of mice for 24-96, 30 h and 10 days caused the development of chromosomal aberrations in bone marrow cells as well as in Dalton's lymphoma (DL) cells, micronuclei (MN) in bone marrow cells and abnormalities in sperm heads, and it indicates the genotoxic potential of cisplatin in the host. Cisplatin exerts differential effects on the chromosomes of the bone marrow and tumor cells. Combination treatment of cisplatin with L-buthionine(S,R)-sulfoximine (BSO), an inhibitor of glutathione (GSH) synthesis, enhanced these cisplatin-induced genotoxic effects, but supplementing glutathione level with cysteine, its precursor, reduced the cisplatin-induced genotoxicity. The reduction in cellular glutathione level may facilitate increased intracellular accumulation and binding of drug to DNA to enhance the frequency of genotoxicity parameters. These findings support the possible involvement of glutathione as an important intracellular protective agent and suggest that differences in its levels may be one of the factors in the varying sensitivity of cells to cisplatin-induced genotoxic effects in the mice bearing ascites Dalton's lymphoma.

Speract induces calcium oscillations in the sperm tail

Sea urchin sperm motility is modulated by sperm-activating peptides. One such peptide, speract, induces changes in intracellular free calcium concentration ([Ca2+]i). High resolution imaging of single sperm reveals that speract-induced changes in [Ca2+]i have a complex spatiotemporal structure. [Ca2+]i increases arise in the tail as periodic oscillations; [Ca2+]i increases in the sperm head lag those in the tail and appear to result from the summation of the tail signal transduction events. The period depends on speract concentration. Infrequent spontaneous [Ca2+]i transients were also seen in the tail of unstimulated sperm, again with the head lagging the tail. Speract-induced fluctuations were sensitive to membrane potential and calcium channel blockers, and were potentiated by niflumic acid, an anion channel blocker. 3-isobutyl-1-methylxanthine, which potentiates the cGMP/cAMP-signaling pathways, abolished the [Ca2+]i fluctuations in the tail, leading to a very delayed and sustained [Ca2+]i increase in the head. These data point to a model in which a messenger generated periodically in the tail diffuses to the head. Sperm are highly polarized cells. Our results indicate that a clear understanding of the link between [Ca2+]i and sperm motility will only be gained by analysis of [Ca2+]i signals at the level of the single sperm.

Fertilization and embryo development in a mouse ICSI model using human and mouse sperm after immobilization in polyvinylpyrrolidone

BACKGROUND

For human ICSI, sperm are normally immobilized immediately prior to injection. However, there are some situations when only sperm of questionable viability are available. There are few evaluations of fertilization or developmental problems in human or animal models using sperm having known intervals between immobilization and injection.

METHODS

Immobilized human sperm were maintained for 1-24 h in 10% polyvinylpyrrolidone (PVP) before injection into mouse oocytes. Mouse sperm heads were similarly maintained in either PVP or a high potassium-containing 'nucleus isolation medium' (NIM) before ICSI and embryo development to the blastocyst stage.

RESULTS

Immobilized human sperm activated mouse oocytes comparably to controls even 24 h after immobilization. However, mouse sperm heads showed a decrease in activating ability 6 h after isolation, either in PVP or NIM. A significant reduction in blastocyst development occurred if mouse sperm heads were maintained for even 1 h in PVP. After 6 h, no blastocysts formed, with arrest occurring at the morula stage. NIM provided partial protection for up to 3 h.

CONCLUSIONS

Immobilized human sperm maintained oocyte activating activity for 24 h. However, mouse sperm are susceptible to alterations that affect both fertilization and development.

Mutagenic effects of carbosulfan, a carbamate pesticide

The genotoxic effects of carbosulfan were evaluated using chromosome aberration (CA), bone marrow micronucleus (MN) and sperm abnormality assays in mice. All the three acute doses (1.25, 2.5 and 5mg/kg) of carbosulfan induced significant dose-dependent increase in the frequency of CA (P<0.02), micronucleated polychromatic erythrocytes (PCEs) (P<0.05) and sperm head abnormalities (P<0.05) but did not affect the total sperm count. The highest acute dose of carbosulfan induced >7-fold increase in the frequency of CA, >3.5-fold increase in the frequency of micronucleated PCEs and >4.6-fold increase in the frequency of sperms with abnormal head morphology following intraperitoneal exposure as compared to the untreated controls. The present findings suggest that carbosulfan is a potent genotoxic agent and may be regarded as a potential germ cell mutagen also.

Capacitation induces cyclic adenosine 3',5'-monophosphate-dependent, but apoptosis-unrelated, exposure of aminophospholipids at the apical head plasma membrane of boar sperm cells

The capacitating agent bicarbonate/CO(2) has been shown to induce profound changes in the architecture and dynamics within the sperm's plasma membrane lipid bilayer via a cAMP-dependent protein phosphorylation signaling pathway. Here we have investigated the effect of bicarbonate on surface exposure of endogenous aminophospholipids in boar spermatozoa, detecting phosphatidylserine (PS) with fluorescein-conjugated annexin V and phosphatidylethanolamine (PE) with fluorescein-conjugated streptavidin/biotinylated Ro-09-0198. Flow cytometric analyses revealed that incubation with 15 mM bicarbonate induced 30%-70% of live acrosome-intact cells to expose PE very rapidly; this exposure was closely related to a decrease in lipid packing order as detected by enhanced binding of merocyanine 540. PS exposure was detectable in the same proportion of cells, though its expression was slower. Confocal microscopy revealed that exposure of aminophospholipids in intact cells was restricted to the anterior acrosomal region of the head plasma membrane. Aminophospholipid exposure, merocyanine stainability, and a subsequent migration of cholesterol to the apical region of the head plasma membrane, were all under the control of the cAMP-dependent protein phosphorylation pathway. The close coupling of decreased lipid packing order with exposure of PE led us to conclude that bicarbonate was inducing phospholipid scrambling (i.e., collapse of asymmetric transverse distribution), and that the scrambling was a prerequisite for cholesterol relocation. There was no evidence whatever that the bicarbonate-induced scrambling was an apoptotic process. It was not accompanied by major loss of viability or by DNA degeneration or by loss of mitochondrial function, and it could not be blocked by the broad-specificity caspase inhibitors zVAD-fmk and BocD-fmk. In the absence of bicarbonate, scrambling could not be induced by the apoptotic agents UV, staurosporine, or cycloheximide. Bicarbonate-induced phospholipid scrambling thus appears to be an important and early physiological event in the capacitation process.

Relationship between bicarbonate and cyclic nucleotide in the promoting effects on head-to-head agglutination in boar spermatozoa

AIM

To clarify the relationship between bicarbonate and cAMP in the promoting effects on the sperm agglutination.

METHODS

Spermatozoa were collected from mature boars, washed and resuspended in a modified Krebs-Ringer HEPES lacking calcium chloride (mKRH). The sperm suspensions were incubated in a water bath (38.5 degrees C) for 60 min and then the percentage of head-to-head agglutinated spermatozoa was determined.

RESULTS

Supplementation of the mKRH with sodium bicarbonate (5-10 mM) significantly raised the percentage of head-to-head agglutinated spermatozoa in the samples. The addition of selective inhibitors for calcium/calmodulin-dependent phosphodiesterases (type 1: 8-methoxymethyl-IBMX and vinpocetine, 25-50 micro M) or for cAMP-specific phosphodiesterases (type 4: Ro20-1724 and rolipram, 25-50 microM) enhanced the effect of bicarbonate on sperm agglutination as highly as did the addition of non-selective inhibitors for phosphodiesterases (IBMX and papaverine, 25-50 microM). A calmodulin antagonist (W-7, 2 microM), that potentially blocks the stimulator of the calcium/calmodulin-dependent phosphodiesterases, significantly enhanced the effect of bicarbonate on sperm agglutination. Moreover, a phosphodiesterase-resistant cAMP analogue (cBiMPS, 0.1 mM) markedly induced agglutination in more spermatozoa (76%) after the incubation without bicarbonate and phosphodiesterase inhibitors than did a less potent cAMP analogue (dibutyryl cAMP, 1 mM) (21%), while three kinds of cGMP analogues (0.1-1 mM) had no effect on sperm agglutination. In addition, a cAMP antagonist (Rp-cAMPS, 1 mM) significantly reduced the sperm agglutination resulting from the actions of bicarbonate and IBMX. On the other hand, the effect of bicarbonate was abolished by a change of incubation temperature from 38.5 degrees C to 25 degrees C.

CONCLUSION

These findings demonstrate that the bicarbonate-induced agglutination of boar spermatozoa is controlled via the cAMP-mediated, temperature-dependent signaling cascade. This cascade is suppressed by the action of the phosphodiesterase (at least types 1 and 4).

Mutagenic profiles of carbazole in the male germ cells of Swiss albino mice

Mutagenic effect of carbazole was evaluated by employing dominant lethal mutation and sperm head abnormality assays in male Swiss albino mice. For the dominant lethal mutation assay, adult male mice were treated for five consecutive days either with 30 or 60 mg/kg body weight (b.w.) of carbazole by single intraperitoneal (i.p.) injection. For the sperm head abnormality assay mice were treated with 50, 100, 150, 200 and 300 mg/kg b.w as a single i.p. injection. Treatment of adult male mice with carbazole resulted in induction of dominant lethal mutation and abnormal sperm heads. The results show that carbazole is mutagenic in male germ cells of mice.