Male-mediated dominant lethal mutations in mice following prooxidant treatment.

This study's primary aim is to examine if prooxidant treatment has the propensity to induce dominant lethal (DL) type mutations in a randomly bred closed colony of CFT-Swiss mice. Initially, graded doses of both organic hydroperoxides viz., t-butyl hydroperoxide (tbHP), and cumene hydroperoxide (cHP) were administered (i.p.) to adult males and the mortality data was analysed to determine the LD(50) values. cHP was relatively more toxic compared to tbHP. The computed LD(50) values were 1500 and 3000 micromol (kg body weight)(-1) for cHP and tbHP, respectively. Subsequently, adult males were administered (i.p.) with 1/10 LD(50) doses of hydroperoxide (HP) (tbHP--30 micromol (100 g body weight)(-1) and cHP - 15 micromol (100 g body weight)(-1)) on 5 consecutive days and were mated with virgin females for a period of 5 weeks to characterise the male-mediated DL mutations. Male-based analysis of the three major variables viz., implantations, live embryos and dead implants (DI) were carried out to assess the DL-type response induction. While tbHP induced significant increases (2- to 5-fold) in the incidence of DI during the first 4 weeks, cHP induced a marginal increase only during the first week. These results suggest that prooxidants induce DL-type effect only in specific post-meiotic stages of spermatogenesis and stress the need to further investigate the implications of chronic oxidative stress on the male reproductive system.     

Protective effects of N-acetylcysteine against arsenic-induced oxidative stress and reprotoxicity in male mice

Arsenic is a well-known environmental toxic metalloid element and carcinogen that affects multiple organ systems including tissue lipid peroxidation and reproduction. The present study was aimed to investigate the protective role of N-acetylcysteine (NAC) on arsenic-induced testicular oxidative damage and antioxidant and steroidogeneic enzymes and sperm parameters in mice. Arsenic was administered through drinking water to mice at a concentration of 4.0 ppm sodium arsenite (actual concentration 2.3 ppm arsenic) for 35 days. The body weight of treated mice did not show significant change as compared with the control mice. In arsenic exposed mice there was a significant decrease in the weight of the testis, epididymis and prostate gland as compared with the control animals. Significant reduction was observed in epididymal sperm count, motile sperms and viable sperms in mice exposed to arsenic indicate decreased spermatogenesis and poor sperm quality. The activity levels of testicular 3β- and 17β-hydroxysteroid dehydrogenases and circulatory levels of testosterone were also decreased in arsenic treated mice indicating reduced steroidogenesis. A significant increase in the activities of lipid peroxidation and a significant decrease in the activities of antioxidant enzymes were observed in the testis of mice exposed to arsenic. In addition, significant increase in the testicular arsenic levels was observed during arsenic intoxication. No significant changes in the oxidation status and selected reproductive variables were observed in the N-acetylcysteine alone treated mice. Whereas, intra-peritoneal injection of NAC to arsenic exposed mice showed a significant increase in the weights of reproductive organs, reduction in arsenic-induced oxidative stress in the tissues and improvement in steroidogenesis over arsenic-exposed mice indicating the beneficial role of N-acetylcysteine to counteract arsenic-induced oxidative stress and to restore the suppressed reproduction in male mice.     

α‐Lipoic acid inhibits testicular and epididymal oxidative damage and improves fertility efficacy in arsenic‐intoxicated rats

The present study evaluates the protective effect of α‐lipoic acid (LA) against arsenic‐induced testicular and epididymal oxidative damage in rats. Arsenic caused significant reduction in the reproductive organ weights, serum testosterone levels, testicular daily sperm count, epididymal sperm count, sperm motility, sperm viability, and sperm membrane integrity. Significant reduction in the activity levels of superoxide dismutase, catalase, and glutathione levels with a concomitant increase in the lipid peroxidation and protein carbonyl content in the testis and the cauda epididymis of arsenic‐exposed rats. Arsenic intoxication also enhanced the testicular caspase‐3 mRNA levels, disorganization of testicular and cauda epididymal architecture as well as increased arsenic content in the testis and the cauda epididymis of rats. Arsenic exposure also deteriorated fertility ability in male rats over controls. Conversely, α‐LA negated the testicular and cauda epididymal oxidative stress and restored the male reproductive health in arsenic‐exposed rats.     

Spermatotoxic effects of α-chlorohydrin in rats

This study was conducted to investigate the potential effects of α-chlorohydrin (ACH) on epididymal function and antioxidant system in male rats. The test chemical was administered to male rats by gavage at doses of 0, 3, 10, and 30 mg/kg/day for 7 days. Twenty-four male rats were randomly assigned to four experimental groups, with six rats in each group. Spermatotoxicity was assessed by measurement of reproductive organ weight, testicular sperm head count, epididymal sperm motility and morphology, histopathologic examination, and oxidative damage analysis in rats. At 30 mg/kg/day, an increase in the incidence of clinical signs, epididymis weight, and gross necropsy findings of the epididymis, a decrease in the sperm motility, and an increased incidence of histopathological changes of the epididymis were observed in a dose-dependent manner. At 10 mg/kg/day, an increased incidence of clinical signs and histopathological changes and decreased sperm motility were observed. In the oxidative damage analysis, an increase in the malondialdehyde concentration and a decrease in the glutathione content and glutathione peroxidase and catalase activities in the epididymal tissue were detected at ≥3 mg/kg/day. The results show that graded doses of ACH elicit depletion of the antioxidant defense system and that the spermatotoxicity of ACH may be due to the induction of oxidative stress.     

Benzo-a-pyrene induced genotoxicity and cytotoxicity in germ cells of mice: Intervention of radish and cress

Exposure to chemicals like benzo(a)pyrene (BaP) can lead to structural changes in DNA and as a consequence to increased incidence of diseases with a genetic basis, as well as oxidative stress in the testis. However its ability to induce oxidative DNA damage in germ cells is not fully investigated. In the present study, BaP was used to induce 8-hydroxydeoxyguanosine (8-OHdG), a specific DNA adducts for oxidative DNA damage, in testis and epididymal sperm and the possible protection role of radish and/or cress was investigated. The results revealed that BaP induced a significant increase in DNA damage in both tissues, as indicated by increased DNA strand breaks in a fluorimetric analysis of DNA unwinding (FADU). Furthermore, it increased the oxidative damage in epididymal sperm, as indicated by the increase in sperm abnormalities, lipid peroxidation (LPO), accompanied with a decrease in glutathione content (GSH), sperm count and sperm motility as well as induction of filtration in the histology of the testis. Treatment with radish and/or cress oil prior to BaP injection succeeded in reducing the germ cell genotoxicity as indicated by the decrease in DNA damage, 8-OHdG levels, sperm abnormalities, LPO level and increased sperm counts, motility and GSH content. Moreover, cress was found to be effective than radish and the combined treatment was more effective than the single treatment. It could be concluded that, pretreatment with radish and/or cress improved the epididymal sperm quality and reduced the genotoxicity and DNA damage induced by BaP, thereby declaring the protective role of radish and cress.     

Exposure to Silica Nanoparticles Causes Reversible Damage of the Spermatogenic Process in Mice

Environmental exposure to nanomaterials is inevitable, as nanomaterials have become part of our daily life now. In this study, we firstly investigated the effects of silica nanoparticles on the spermatogenic process according to their time course in male mice. 48 male mice were randomly divided into control group and silica nanoparticle group with 24 mice per group, with three evaluation time points (15, 35 and 60 days after the first dose) per group. Mice were exposed to the vehicle control and silica nanoparticles at a dosage of 20 mg/kg every 3 days, five times over a 13-day period, and were sacrificed at 15, 35 and 60 days after the first dose. The results showed that silica nanoparticles caused damage to the mitochondrial cristae and decreased the levels of ATP, resulting in oxidative stress in the testis by days 15 and 35; however, the damage was repaired by day 60. DNA damage and the decreases in the quantity and quality of epididymal sperm were found by days 15 and 35; but these changes were recovered by day 60. In contrast, the acrosome integrity and fertility in epididymal sperm, the numbers of spermatogonia and sperm in the testes, and the levels of three major sex hormones were not significantly affected throughout the 60-day period. The results suggest that nanoparticles can cause reversible damage to the sperms in the epididymis without affecting fertility, they are more sensitive than both spermatogonia and spermatocytes to silica nanoparticle toxicity. Considering the spermatogenesis time course, silica nanoparticles primarily influence the maturation process of sperm in the epididymis by causing oxidative stress and damage to the mitochondrial structure, resulting in energy metabolism dysfunction.     

Effects of boric acid feeding on the oxidative stress parameters in testes,sperm parameters and DNA damage in mice

This study was aimed to determine the effects of boric acid on oxidative stress, testicular tissue and spermatozoon DNA. Experiments were performed with Swiss Albino mice divided equally into two groups based on the tratment period: one for 4 and the other for 6-week duration. These groups were further divided into subgroups as Control and those administered daily at oral doses of 115 mg/kg, 250 mg/kg and 450 mg/kg of boric acid. Then, testicular tissue were examined postmortem and analyzed using ex-vivo biochemical tools for oxidative stress, spermatozoon membrane integrity, sperm motility and live cell rate (%). In both 4 and 6-week groups, v. seminalis weight, membrane integrity, motility, live cells and GSH levels exhibited a decreasing trent compared to the controls. In addition, 6-week group had a decrease in SOD level. MDA level was higher in controls in both 4 and 6-week groups. Spermatozoon DNA was intact in the 4-week group, but damaged in the 6-week group, and the degree of the damage dependent on the administered dose. Boric acid induces oxidative stress in testicular tissue, and its long-term application (only 6 weeks) caused damage in spermatozoon DNA.     

Dacarbazine induces genotoxic and cytotoxic germ cell damage with concomitant decrease in testosterone and increase in lactate dehydrogenase concentration in the testis

Treatment of cancers with cytotoxic agents such as alkylating drugs often, but not always results in transient to permanent testicular dysfunction. The present study was planned to investigate the effects of dacarbazine [5-(3,3-dimethyltriazeno) imidazole-4-carboxamide] on testicular function in mice. Swiss albino mice (9-12 weeks old) were treated with 0, 5, 25, 50, or 100mg/kg body weight/day dacarbazine (i.p.) for 5 days at intervals of 24h between treatments. Mice were sacrificed on days 7, 14, 21, 28, 35, 49, and 70 after the last treatment (6 mice/dose/sample time), and the epididymal sperm count, sperm motility, sperm morphology, testicular histopathology (qualitative histopathology, seminiferous tubular diameter and epithelial height), and intra-testicular levels of testosterone and lactate dehydrogenase were assessed. Dacarbazine decreased the body weight only on day 28 at 25mg/kg dose-level, but increased the paired testes weights at 50mg/kg on day 7, at 25-100mg/kg on day 14, and at 25 and 50mg/kg on day 21 (P<0.05-0.01; one-way ANOVA and Bonferroni's post hoc test). The sperm count was decreased on all sampling days except at 5 and 25mg/kg dose-levels on day 70, but with severe oligospermia on days 28 and 35 (P<0.05-0.001). The sperm motility was decreased at 100mg/kg on days 14 and 21, at 5, 25, and 100mg/kg on day 28, and at all dose-levels on day 35 (P<0.05-0.001). Dacarbazine induced both head and tail abnormalities and some sperms with cytoplasmic droplets, but significant increase was seen in all dose groups on days 14 and 21, and at 100mg/kg dose-level on day 35. Drug-induced epithelial sloughing was seen on days 14-35 and other histopathological changes observed were vacuoles and abnormal cells. The STD was increased at 25-100mg/kg on day 7, at all dose-levels on day 14, at 50-100mg/kg on days 21 and 28, but without any effects on days 35-70 (P<0.05-0.001), and the tubular lumen was found dilated. The SE was increased on days 7, 21 and 28 at 100mg/kg and on day 14 at 50-100mg/kg. Dacarbazine reduced the intra-testicular testosterone level at 100mg/kg on day 7, at 5, 50 and 100mg/kg on day 14, at all dose-levels on days 21, 28, and 35, and at 50mg/kg on day 49 (P<0.05-0.001). The intra-testicular lactate dehydrogenase concentration increased at all dose-levels up to day 35, but without any effect on days 49 and 70 (P<0.05-0.001). There was no particular dose-response of dacarbazine on any parameters tested. The sperm count (except on day 7-positive correlation; Pearson product moment correlation) or sperm motility did not have any relation but increase in abnormal sperms showed negative correlation with decrease in testosterone level on days 7, 21 and 28. Decrease in sperm count was in negative correlation on days 14 and 35, and increase in abnormal sperms showed positive correlation on day 35 with increase in LDH level. Finally, the decrease in sperm motility had no correlation with increase in abnormal sperm shapes. We conclude that dacarbazine is genotoxic and cytotoxic to the mouse testis in a transient fashion, and these effects are exerted along with decrease in testosterone and increase in lactate dehydrogenase levels in the testis.     

Absence of in vivo mutagenic potency of heated and fried oils in mice.

The mutagenic potency of heated and fried oils (under laboratory conditions), viz. peanut, sesame and coconut oils were studied employing two well validated in vivo mammalian assays, viz. bone marrow micronucleus assay and the sperm morphology assay in albino mice. In the bone marrow micronucleus assay oral doses of fresh, heated and fried oils (7.5 ml and 30.0 ml/kg body weight) did not induce any increase in the incidence of micronucleated polychromatic erythrocytes. Intragastric administration of oils at the highest dose (30.0 ml/kg body weight/day) for 5 consecutive days in male mice did not produce any morphological effect either on the testicular or epididymal weights and histology. No significant alterations were observed in the caudal sperm counts at any of the sampling intervals and also there was no treatment related increase in the incidence of sperm head abnormalities. It is concluded that controlled thermal treatment as well frying of these oils did not produce appreciable amount of mutagens which could be detected under in vivo situations.     

Lycopene protects against cyclosporine A-induced testicular toxicity in rats

Cyclosporine A (CsA)-induced direct failures in hypothalamic-pituitary-gonadal axis and Sertoli cell phagocytic function have been considered for testicular toxicity so far. It has clearly been reported that oxidative stress leads to damage in sperm functions and structure of the testis. Therefore, this study was conducted to demonstrate whether CsA causes testicular and spermatozoal toxicity associated with the oxidative stress, and to investigate the possible protective effect of lycopene against CsA-induced damages in all reproductive organs and sperm characteristics in male rats. While the daily administration of CsA at the dose 15 mg/kg for 21 days significantly decreased the seminal vesicles weight, epididymal sperm concentration, motility, testicular tissue glutathione (GSH), glutathione peroxidase (GSH-Px) and catalase (CAT), diameter of seminiferous tubules and germinal cell thickness, it increased malondialdehyde (MDA) level and abnormal sperm rates along with degeneration, necrosis, desquamative germ cells in testicular tissue. However, the CsA along with simultaneous administration of lycopene at the dose of 10mg/kg markedly ameliorated the CsA-induced all the negative changes observed in the testicular tissue, sperm parameters and oxidant/antioxidant balance. In conclusion, CsA-induced oxidative stress leads to the structural and functional damages in the testicular tissue and sperm quality of rats and, lycopene has a potential protective effect on these damages.     

Spermatogenesis parameters and testosterone production at puberty as predictors of testicular functional activity in mice (<Emphasis Type="Italic">Mus musculus</Emphasis>)

The aim of this study was to investigate fertility-associated parameters of spermatogenesis and androgenic status in male laboratory mice at puberty and to assess their prognostic significance in the realization of the definitive testicular function. In three inbred murine strains, BALB/cLac, CBA/Lac and PT, the serum testosterone level, its testicular concentration, epididymal sperm count (sperm reserve) and portion of sperm with abnormal head morphology were evaluated on days 45 (puberty) and 90 (adulthood) of postnatal development. CBA/Lac males were characterized by a lower epididymal sperm count vs. other strains at both ages indicative of poorer spermatogenesis. At the same time, CBA/Lac males had a lower portion of sperm with abnormal head morphology, and this could be considered as a compensatory reaction aimed at improving sperm fertility. Distinct inter-strain differences in the portion of sperm with morphologically abnormal heads were established at both ages, while the inter-strain ratio remained invariable (BALB/cLac > PT > CBA/Lac). Thus, the level of abnormal spermatogenesis in the pubertal period may have a predictive significance for the definitive testicular activity in adult mice. No inter-strain and age-dependent changes were found in serum and testicular testosterone levels except for the PT strain, in which both testosterone levels rose from puberty to adulthood, suggesting a shift of the pubertal testosterone peak towards later times. Our data show that in male laboratory mice the genetic peculiarities of the testicular function manifest themselves during puberty and persist until adulthood.     

Mechanisms of damage to sperm structure in mice on the zinc-deficient diet

BackgroundZinc (Zn)is an essential trace element for spermatogenesis and its deficiency causes abnormal spermatogenesis.ObjectiveThe present study was conducted to examine the mechanisms by which Zn-deficient diet impairs sperm morphology and its reversibility.Methods30 SPF grade male Kunming (KM) mice were randomly divided into three groups, 10 mice per group. Zn-normal diet group (ZN group) was given Zn-normal diet（Zn content= 30 mg/kg）for 8 weeks. Zn-deficienct diet group (ZD group) was given Zn-deficienct diet（Zn content< 1 mg/kg）for 8 weeks. Zn-deficient and Zn-normal diet group（ZDN group）was given 4 weeks Zn-deficienct diet followed by 4 weeks Zn-normal diet. After 8 weeks, the overnight fasted mice were sacrificed, and blood and organs were collected for further analysis.ResultsThe experimental results showed that Zn-deficienct diet leads to increased abnormal morphology sperm and testicular oxidative stress.The rate of abnormal morphology sperm, chromomycin A3(CMA3), DNA fragmentation index (DFI), malondialdehyde (MDA) were significantly increased, and a-kinase anchor protein 4(AKAP4), dynein axonemal heavy chain 1(DNAH1), sperm associated antigen 6(SPAG6), cilia and flagella associated protein 44(CFAP44), glutathione peroxidase (GSH-PX), superoxide dismutase (SOD), total antioxidant capacity (T-AOC), nuclear factor erythroid 2-related factor (NRF2), NAD(P)H:quinone oxidoreductase 1(NQO1)and heme oxygenase 1(HO1) were significantly decreased in the ZD group mice. While the changes in above indicators caused by Zn-deficient diet were significantly alleviated in the ZDN group.ConclusionIt was concluded that Zn-deficient diet causes abnormal morphology sperm and testicular oxidative stress in male mice. Abnormal morphology sperm caused by Zn-deficient diet are reversible, and Zn-normal diet can alleviate them.     

Epididymal SPAM1 is a marker for sperm maturation in the mouse

Sperm adhesion molecule 1 (SPAM1), is a glycosyl phoshatidylinositol-linked sperm membrane protein that is dually expressed in testis and epididymis. Epididymal SPAM1 is secreted in all three regions of the epididymis in all mammalian species studied, including humans. It shares the same molecular mass and neutral hyaluronidase activity as the testicular and sperm isoforms that are responsible for the penetration of the cumulus during fertilization. Using wild-type (W/T) sperm and those from mice homozygous for either a null (Spam1-/-) or mutant Spam1 allele, which results in decreased mRNA and protein, we demonstrate that sperm binding of epididymal SPAM1 occurs in vitro after exposure to W/T sperm-free epididymal luminal fluid (ELF). Binding or adsorption that occurred after incubation at room temperature or 32 degrees C was detected immunocytochemically and confirmed quantitatively using flow cytometry. The localization of SPAM1 on the plasma membrane of Spam1-null sperm mimicked that seen in the W/T. The remarkable increase in binding on W/T caudal sperm indicates that they are not fully saturated with SPAM1 during storage, and suggests that uptake of epididymal SPAM1 in vivo augments testicular SPAM1. Spam1-null sperm exposed to W/T ELF for 45-60 min during in vitro capacitation to allow epididymal SPAM1 binding showed a highly significant (P < 0.001) increase in cumulus penetration after 6-7 h compared to those incubated in ELF from null males. Similarly, the number of cumulus-free oocytes was also highly significantly greater (P < 0.001) than that for sperm capacitated in W/T SPAM1-antibody-inhibited ELF. Because epididymal SPAM1 uptake significantly increases cumulus penetration, we conclude that it is a marker of sperm maturation.     

Iron-induced oxidative DNA damage in rat sperm cells in vivo and in vitro

We investigated whether acute iron intoxication causes oxidative DNA damage, measured in terms of 7-hydro-8-oxo-2'-deoxyguanosine, 8-oxodG, in nuclear DNA in testes and epididymal sperm cells in vivo and in vitro in rats. In addition, we investigated levels of the modified nucleoside in liver and kidney and measured its urinary excretion. Sperm cells were isolated from the epididymides and the testes cells were isolated after homogenisation. In vitro, the sperm and testes cells were incubated with increasing concentrations of FeCl2 ranging from 0 to 600 microM. The median (range) levels of 8-oxodG/10(5) dG in the epididymal sperm cells increased from 0.48 (0.42-0.90) to 15.1 (11.4-17.6) (p < 0.05), whereas the level rose from 0.63 (0.22-0.81) to 8.8 (4.5-11.6) (p < 0.05) at 0 and 600 microM, respectively, in the testicular cells. In vivo groups of 7-8 rats received 0, 200 or 400 mg iron/kg as dextran i.p. After 24 h, epididymal sperm cells, testes, kidneys and liver were collected for analysis. Kidney and sperm DNA showed a significant increase in 8-oxodG in the iron-treated animals. The median (range) values of the 8-oxodG/10(5) dG in the epididymal sperm cells rose from 0.66 (0.38-1.09) to 1.12 (0.84-5.88) (p < 0.05) at 0 and 400 mg iron/kg, respectively, whereas the values in the testes and liver showed no significant change. In the kidneys the 8-oxodG/10(5) dG median (range) values were 0.98 (0.73-1.24), 1.21 (1.13-1.69) and 1.34 (1.12-1.66) after 0, 200 and 400 mg iron/kg, respectively (p < 0.05). The 8-oxodG-excretion rate was measured in 24h urine before and after iron treatment. The rate of urinary 8-oxodG excretion increased from 129 (104-179) pmol/24 h before treatment to 147 (110-239) pmol/24 h after treatment in the group receiving 400 mg iron/kg (p < 0.05). The results indicate that acute iron intoxication may increase oxidative damage to sperm and kidney DNA.     

Development to blastocyst is impaired when intracytoplasmic sperm injection is performed with abnormal sperm from infertile mice harboring a mutation in the protein phosphatase 1cgamma gene

Idiopathic azoospermia, characterized by abnormal spermatogenesis, is commonly treated by performing intracytoplasmic sperm injection (ICSI) with sperm retrieved from testicular biopsies. However, no controlled experiments have been performed using an animal model to assess the efficacy or safety of the procedure. We have performed ICSI with testicular sperm obtained in a similar manner from testes of male mice homozygous for a null mutation in the protein phosphatase 1cgamma gene (PP1cgamma) or those of their wild-type littermates. PP1cgamma mutant testicular sperm are less resistant to sonication than are wild-type sperm and display a range of morphological abnormalities, similar to those reported for testicular sperm from idiopathic azoospermic men. PP1cgamma mutant sperm are unable to support development to the blastocyst stage, resulting in arrested development either before or just after compaction. A comparison of testicular and epididymal sperm from wild-type males revealed that the epididymal sperm caused embryos to fragment at an elevated rate. These results suggest that ICSI with any kind of testicular sperm carries an increased risk of embryo fragmentation and that abnormal testicular sperm has an added risk of embryo wastage at later preimplantation stages.     

Targeted disruption of the transition protein 2 gene affects sperm chromatin structure and reduces fertility in mice

During mammalian spermiogenesis, major restructuring of chromatin takes place. In the mouse, the histones are replaced by the transition proteins, TP1 and TP2, which are in turn replaced by the protamines, P1 and P2. To investigate the role of TP2, we generated mice with a targeted deletion of its gene, Tnp2. Spermatogenesis in Tnp2 null mice was almost normal, with testis weights and epididymal sperm counts being unaffected. The only abnormality in testicular histology was a slight increase of sperm retention in stage IX to XI tubules. Epididymal sperm from Tnp2-null mice showed an increase in abnormal tail, but not head, morphology. The mice were fertile but produced small litters. In step 12 to 16 spermatid nuclei from Tnp2-null mice, there was normal displacement of histones, a compensatory translationally regulated increase in TP1 levels, and elevated levels of precursor and partially processed forms of P2. Electron microscopy revealed abnormal focal condensations of chromatin in step 11 to 13 spermatids and progressive chromatin condensation in later spermatids, but condensation was still incomplete in epididymal sperm. Compared to that of the wild type, the sperm chromatin of these mutants was more accessible to intercalating dyes and more susceptible to acid denaturation, which is believed to indicate DNA strand breaks. We conclude that TP2 is not a critical factor for shaping of the sperm nucleus, histone displacement, initiation of chromatin condensation, binding of protamines to DNA, or fertility but that it is necessary for maintaining the normal processing of P2 and, consequently, the completion of chromatin condensation.     

Modulatory role of lipoic acid on adriamycin-induced testicular injury

The present study investigated the protective efficacy of dl-alpha-lipoic acid (LA) on adriamycin (ADR)-induced oxidative damage in rat testis. Adult male albino rats of Wistar strain were administered ADR (1 mg/kg body weight, i.v.), once a week for 10 weeks. ADR injected rats showed increased oxidative stress with a concomitant decrease in cellular thiols. The mRNA level for phospholipid hydroperoxide glutathione peroxidase (PHGPx) was also significantly decreased by ADR administration. Transmission electron microscopic (TEM) observations of testicular germ cells revealed abnormal ultrastructural changes in ADR treated rats. Treatment with lipoic acid (35 mg/kg body weight, i.p.) 1 day prior to ADR administration, effectively reverted these abnormal changes towards normalcy. These findings indicate a cytoprotective role of LA in this experimental model of testicular toxicity.     

Hydroxyurea exposure alters mouse testicular kinetics and sperm chromatin structure

Abstract. The effects of hydroxyurea (HU) on testicular cell kinetics and sperm chromatin differentiation were investigated in mice. Whole testis, minced testicular cell suspensions and caudal epididymal sperm cells were obtained at 8 and 29 days after i.p. injections containing 0, 25, 50, 100, 200, 400 and 500 mg/kg HU X 5 days. Testis weights were unaffected by 25 mg/kg HU while 500 mg/kg caused up to a 50% loss of testicular weight by 29 days. Flow cytometrically measured acridine-orange (AO) stained testicular cells revealed altered population ratios at the highest dosages at 8 days and for all dosages except 25 mg/kg HU at 29 days. At 8 days, 400–500 mg/kg HU caused a near depletion of tetraploid cells. Flow cytometry of AO stained sperm, previously treated with acid to potentially induce DNA denaturation, was used to follow the shift from normal chromatin structure to an abnormal form with increased sensitivity to DNA denaturation in situ. The extent of DNA denaturation was quantitated for each cell by the computer-derived value alpha t, α_t= [red/(red+green) fluorescence]. The flow cytometry measures, standard deviation of α_t (SDα_t), mean of α_t (Xα_t) and cells outside the main peak of α_t (COMPα_t), gave similar dose response curves to the sperm head morphology assay. SDα_t was more sensitive than the Xα_t as a measure of HU-induced alteration of chromatin structure. The major conclusions reached are that HU inhibits DNA synthesis, probably by inhibiting ribonucleotide reductase, causing maturation depletion of pachytene spermatocytes and, subsequently, depletion of meiotic daughter cells and differentiated cell types leading to mature sperm. This inhibition of DNA synthesis is related to an alteration of sperm chromatin structure and abnormal sperm head morphology.     

Induction of shape abnormality and unscheduled DNA synthesis by arecoline in the germ cells of mice

The ability of arecoline, an alkaloid of betel nut, to induce abnormality in the shape of sperm heads and unscheduled DNA synthesis (UDS) in the early spermatid stages of Swiss albino mice was studied. Treatment of mice with arecoline at the dose levels of 20, 40 and 80 mg/kg elicited dose-related increase in the number of abnormal sperm heads, as well as the unscheduled incorporation of [3H]thymidine into the DNA of early spermatids. Such increase in the production of abnormally shaped sperms and UDS response of the early spermatids following arecoline treatment expressed its genotoxic potential in the mouse germ cells.     

Zinc protects cyclophosphamide-induced testicular damage in rat: Involvement of metallothionein,tesmin and Nrf2

The role of zinc (Zn) in the protection of germ cells against testicular toxicants has long been elucidated, but the exact molecular mechanisms have not yet been explored. Cyclophosphamide (CP), one of the most commonly used anticancer drugs survived ages of treatment, but the unwanted toxicity limits its clinical usage. The present investigation was aimed to explore the role of Zn and its associated pathways in CP-induced testicular toxicity in S.D. rat. CP was administered in saline 30 mg/kg 5× weekly for 3 weeks (total dose of 450 mg/kg) by i.p. route, while Zn was supplemented by oral route at the doses of 1, 3, 10 mg/kg/day for 3 weeks. CP significantly reduced Zn levels in serum and testes, body and testicular weight, sperm count and motility, spermiogenic cells, plasma testosterone and significantly increased the oxidative stress, sperm head abnormalities, sperm DNA damage with decreased chromatin and acrosome integrity; while Zn supplementation ameliorated the same. The present results demonstrated that Zn supplementation protected against CP-induced testicular damages by modulating metallothionein (MT), tesmin and Nrf2 associated pathways. Thus Zn supplementation during anticancer therapy might be potentially beneficial in reducing the off target effects associated with oxidative stress.