The effect of L-acetylcarnitine on some reproductive functions in the oligoasthenospermic rat

The effect of L-acetylcarnitine (LAC) on some parameters of male reproductive function was studied on rats made oligoasthenospermic with dibromochloropropane (DBCP). DBCP depresses sperm count and motility. After one injection of the drug, LAC induces a recovery of both sperm count and motility but after two injections it is ineffective. This effect is also shown visually by microscopic examination of seminiferous tubules. Among the enzymatic activities evaluated as biochemical markers of testicular function both lactate dehydrogenase and NADPH-cytochrome P 450-reductase increased significantly (P less than 0.05) after treatment with LAC in normal rats. LAC also stimulates testosterone production. It is suggested that LAC may affect testicular function.     

Comparative toxicity of (+)-(R)- and (−)-(S)-1,2-dibromo-3-chloropropane

The haloalkane 1,2-dibromo-3-chloropropane (DBCP), an environmental pollutant that was widely used as a soil fumigant, is a carcinogen and a mutagen and displays target-organ toxicity to the testes and the kidneys. Because little is known about effects of stereochemistry on the metabolism and toxicity of halogenated alkyl compounds and because DBCP, which has a chiral center at C-2, may show enantioselectivity in its metabolism and/or toxicities, the optically pure enantiomers of DBCP were tested in vivo in rats for organ toxicity as well as for bacterial mutagenicity. Organ toxicity studies showed that (S)-DBCP was slightly more renal toxic than (R)-DBCP but was not significantly more toxic than the racemate, and that no significant differences were observed in the extents of testicular necrosis and atrophy caused by either enantiomer or the racemate. In contrast, (R)-DBCP was more mutagenic than either (S)-DBCP or the racemate to Salmonella typhimurium (S. typhimurium) strains TA 100 and TA104. However, there was little or no enantioselectivity in glutathione S-transferase (GST)-catalyzed conjugation reactions of glutathione with DBCP based on the lack of selectivity in the rates of disappearance of the enantiomers of DBCP in the presence of glutathione (GSH) and GSTs as monitored by chiral gas chromatography (GC). © 1995 Wiley-Liss, Inc.     

Metabolism of selectively methylated and deuterated analogs of 1,2-dibromo-3-chloropropane: role in organ toxicity and mutagenicity

In vitro bromide release and in vivo glutathione (GSH) depletion in rat liver, kidney and testis by 1,2-dibromo-3-chloropropane (DBCP) and selectively methylated and deuterated DBCP analogs were studied. With liver microsomes from phenobarbital-pretreated rats the bromide release from the C1-C3-D4- and the perdeuterated DBCP analogs were 54% and 26% of that of DBCP, respectively. Inhibitors of P-450 reduced the bromide release to 10-20% of that without additions. This correlated with the effects of deuterium substitution and additions of P-450 inhibitors on DBCP-induced bacterial mutagenicity as reported elsewhere by this laboratory. To study the importance of GSH-dependent metabolism in DBCP toxicity, bromide release was assayed in cytosolic preparations using methylated analogs of DBCP. With the C1-methyl-derivative, bromide release was markedly reduced compared to that with DBCP in cytosols from liver, kidney and testis. A similar reduction in in vivo nephrotoxicity and testicular damage has recently been reported. The obtained correlation between in vitro GSH-dependent metabolism of methylated DBCP analogs and their in vivo organ damaging potential, points to an involvement of GSH-dependent metabolism in DBCP-induced in vivo toxicity. Both DBCP and the methylated analogs (360 mumol/kg i.p.) depleted the GSH levels in liver after 1 and 3 h and in kidney after 1 h, whereas in the testis no significant depletion of GSH was obtained. As kidney and testis are reported to be the primary target organs for DBCP, there was an apparent lack of correlation between tissue depletion of GSH and organ toxicity.     

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.     

Effect of DNOC, Ferbam and Imidan exposure on mouse sperm morphology

DNOC, Ferbam and Imidan were tested in (C3H X C57BL/6) F1 mice to assess their potential testicular toxicity. Chemicals were administered i.p. and per os at different doses for 5 consecutive days. After 35 days the testicular was toxicity was evaluated by measuring the testicular weights, the sperm counts and the percentage of abnormal sperm. DNOC and Imidan failed to induce teratospermia in mice treated by both routes of administration. Conversely Ferbam induced a statistically significant increase in teratospermia only following per os administration to mice at a dose of 1000 mg/kg b.w./day. These data indicate that per os administration of Ferbam succeeded in producing active metabolites able to interfere with the differentiation process of spermatogenic cells.     

小鼠睾丸注射不同转染试剂和注射方法对外源基因表达的影响

为探讨不同转染试剂(LipofectamineTM LTXPLUSTM、Lipofectamine2000和纳米化聚酰胺-胺型树枝状聚合物(PAMAM-D))和睾丸注射方法 (睾丸网注射、曲精细管注射和间质注射)对转基因小鼠生产效率的影响,将pEGFP-C1质粒分别与不同转染试剂混合后,按照不同的注射方法注入小鼠睾丸内,30 d后检测小鼠精子密度、活力、精子阳性率以及配种后仔鼠转基因阳性率。结果 3种转染试剂对小鼠繁殖性能影响由小到大依次为LipofectamineTM LTXPLUSTM、Lipofectamine 2000和PAMAM-D。转染后LipofectamineTM LTXPLUSTM、Lipofectamine 2000和PAMAM-D组精子的GFP阳性率分别为35.65%±0.69%、12.86%±0.35%和10.04%±0.20%。配种后仔鼠的PCR阳性率分别为29.17%、13.70%和5.88%。3种不同注射方法对小鼠睾丸都造成损伤,由小到大依次为睾丸网注射、曲精细管注射和睾丸间质注射,三者的阳性精子比例分别为35.13%±1.727%、15.13%±1.457%和0%,配种后仔鼠的PCR阳性率分别为33.3%、12.5%和0%。结果表明,LipofectamineTM LTXPLUSTM和睾丸网注射对小鼠睾丸的损伤最小,并能获得较高的转染效率。     

Morin mitigates cadmium-induced testicular impairment by stimulating testosterone secretion and germ cell proliferation in mice

Cadmium (Cd) is one of the heavy metal pollutants present in the environment due to human intervention. It is well known that Cd causes toxicological effects on various organs, including the testes. Morin hydrate is a plant-derived bioflavonoid with antioxidant, anti-inflammatory, and anti-stress properties. Thus, the question can be raised as to whether Morin has an effect on Cd-intoxication-induced testicular impairment. Therefore, the aim of this study was to investigate the role of Morin on Cd-mediated disruption of testicular activity. Mice were divided into three groups: group 1 served as the control group, group 2 was given Cd (10 mg/kg) orally for 35 days, and group 3 was given Cd and Morin hydrate (100 mg/kg) for 35 days. To validate the in vivo findings, an in vitro study on testicular explants was also performed. The results of the in vivo study showed that Cd-intoxicated mice had testicular disorganization, reduced circulating testosterone levels, decreased sperm density, and elevated oxidative stress and sperm abnormality. The expression of the germ cell proliferation marker, germ cell nuclear acidic protein (GCNA), and adipocytokine visfatin were also downregulated. It was observed that Morin hydrate upregulated testicular visfatin and GCNA expression in Cd-intoxicated mice, along with improvement in circulating testosterone, testicular histology, and sperm parameters. Furthermore, the in vitro study showed that Cd-mediated downregulation of testicular visfatin and GCNA expression, along with the suppressed secretion of testosterone from testicular explants, was normalized by Morin treatment, whereas visfatin expression was not. Overall, these data indicate that environmental cadmium exposure impairs testicular activity through downregulation of visfatin and GCNA expression, and Morin might play a protective role against Cd-induced testicular toxicity.     

Involvement of testicular DAAM1 expression in zinc protection against cadmium‐induced male rat reproductive toxicity

In order to verify the effects of exposure to Cd and Zn on testicular DAAM1 gene and protein expression and also to ascertain their involvement in the protective role of Zn in prevent the testicular toxicity Cd‐induced in male offspring rats at adult age after gestational and lactational exposure, male offspring rats, from mothers receiving either tap water, Cd, Zn, or Cd + Zn during gestation and lactation periods, were scarified on postnatal days (PND) 70. The reproductive organ (testis, epididymis, and vesicle seminal) were collected, weighed, and analyzed. The results showed that exposure to Cd in utero and through lactation decreased the relative reproductive organ weight, altered the testicular histology at the interstitial and tubular levels, and causing a significant reduction in the daily sperm production (DSP) per testis and per gram of testis, and other then altering the epididymal sperm quality. Furthermore, both mRNA and protein expression of rat testicular DAAM1 were also inhibited in Cd‐treated group. Zn supply has completely corrected the most of these toxic effects. Our results imply that Zn could prevent Cd‐induced testicular toxicity and sperm quality alteration in adult male rat after gestational and lactational exposure, probably via the restoration of the testicular DAAM1 expression inhibited by Cd.     

Forskolin ameliorates mancozeb‐induced testicular and epididymal toxicity in Wistar rats by reducing oxidative toxicity and by stimulating steroidogenesis

In the present study, we have tested the beneficial effects of forskolin in protecting the mancozeb‐induced reproductive toxicity in rats. Adult male Wistar rats were exposed to either mancozeb (500 mg/kg body weight/day) or forskolin (5 mg/kg body weight/day) or both for 65 days and analyzed for spermatogenesis and steroidogenesis and testicular and epididymal oxidative toxicity. A significant decrease in daily sperm production, epididymal sperm count, motile, viable, and hypo‐osmotic swelling‐tail swelled sperm was observed in mancozeb‐treated rats. The activity levels of testicular 3β‐hydroxysteroid dehydrogenase and 17β‐hydroxysteroid dehydrogenase and circulatory testosterone levels were significantly decreased in mancozeb‐treated rats. Exposure to mancozeb resulted in a significant decrease in glutathione levels and superoxide dismutase and catalase activity levels with an increase in lipid peroxidation levels in the testes and epididymis. Coadministration of forskolin mitigated the mancozeb‐induced oxidative toxicity and suppressed steroidogenesis and spermatogenesis.     

Genetic toxicology of 1,2-dibromo-3-chloropropane (DBCP)

1,2-Dibromo-3-chloropropane (DBCP) is a nematocide, which has been used extensively as a soil fumigant in agriculture. Since sterility was found among male workers involved in the manufacture of DBCP, great concern has been focused on the genetic hazards of DBCP. DBCP gave positive results in many tests such as microbial, in vitro cytogenetics, and Drosophila studies. In mammalian test systems, DBCP caused chromosomal aberrations in the bone marrow cells and dominant-lethal mutations in germ cells in rats. In mice, there were no signs of DBCP-induced heritable mutation in germ cells, although point mutations were detected in somatic cells. The occurrence of Y-chromosomal non-disjunction was indicated in DBCP-exposed male workers by an increased number of sperm containing 2 Y-chromosomes.     

Protective Effect of Selenium on Nicotine-Induced Testicular Toxicity in Rats

Effect of exogenous selenium at a dose of 10 mug/kg body weight on the testicular toxicity induced by nicotine in rats was investigated. Male albino rats were maintained for 60 days as follows: (1) control group (normal diet), (2) nicotine group (0.6 mg /kg body weight), (3) selenium (10 microg/kg body weight), and (4) nicotine (0.6 mg/kg body weight) + selenium (10 microg/ kg body weight). Administration of nicotine caused reduction in sperm count and sperm motility. Activity of HMG CoA reductase and concentration of cholesterol were increased in the testes of the nicotine administered group. Activities of testicular enzymes 3beta hydroxysteroid dehyrogenase (3 betaHSD), 17beta hydroxysteroid dehyrogenase (17 betaHSD) were decreased. Levels of testosterone in the serum were also reduced. However, the extent of these alterations was lesser in the group administered with nicotine along with selenium. Analysis of plasma revealed reduced quantity of cotinine in the group co-administered with nicotine along with selenium in comparison with the nicotine group. Nondetectable levels of nicotine were present in the co-administered group. This indicates altered metabolism of nicotine when administered along with selenium.     

Generation of Live Piglets for the First Time Using Sperm Retrieved from Immature Testicular Tissue Cryopreserved and Grafted into Nude Mice

Cryopreservation of immature testicular tissues is essential for increasing the possibilities of offspring generation by testicular xenografting for agricultural or medical purposes. However, successful production of offspring from the sperm involved has never been reported previously. In the present study, therefore, using intracytoplasmic sperm injection (ICSI), we examined whether xenogeneic sperm obtained from immature pig testicular tissue after cryopreservation would have the capacity to produce live piglets. Testicular fragments from 9- to 11-day-old piglets were vitrified after 10- or 20-min immersion in vitrification solution containing ethylene glycol (EG), polyvinyl pyrrolidone (PVP) and trehalose as cryoprotectants, and then stored in liquid nitrogen for more than 140 days. Thirty nude mice were assigned to each immersion-time group. Testicular fragments were transplanted under the back skin of castrated mice immediately after warming and removal of the cryoprotectants. Blood and testicular grafts were then recovered from the recipient mice on days 60, 120, 180 and 230−350 (day 0 =  grafting). Histological assessment of the testicular grafts and analyses of inhibin and testosterone production revealed no significant differences between the two immersion-time groups, indicating equal growth activity of the cryopreserved tissues. A single sperm obtained from a mouse in each group on day 230−350 was injected into an in vitro-matured porcine oocyte, and then the ICSI oocytes were transferred to the oviducts of estrus-synchronized recipient gilts. One out of 4 gilts that had received oocytes fertilized using sperm from the 10-min immersion group delivered 2 live piglets, and one of another 4 gilts from the 20-min group delivered 4 live piglets. Thus, we have successfully generated porcine offspring utilizing sperm from immature testicular tissues after cryopreservation and transplantation into nude mice. The present model using pigs will be applicable to many large animals, since pigs are phylogenetically distant from the murine recipients.     

Metabolic activation of 1,2-dibromo-3-chloropropane: evidence for the formation of reactive episulfonium ion intermediates

The nematocide and soil fumigant 1,2-dibromo-3-chloropropane (DBCP) is a carcinogen and a mutagen and displays target-organ toxicity to the testes and the kidney. It has been proposed that both cytochrome P-450 mediated activation and glutathione (GSH) conjugation pathways are operative in DNA damage and organotropy induced by DBCP. To determine the chemical mechanisms involved in the bioactivation of DBCP and to assess a role for an episulfonium ion intermediate, the mechanism of formation of GSH conjugate metabolites of DBCP was investigated. Five biliary GSH conjugates of DBCP were isolated from rats and identified by fast atom bombardment tandem mass spectrometry: S-(2,3-dihydroxy-propyl)glutathione (I), S-(2-hydroxypropyl)glutathione (IIA), S-(3-chloro-2-hydroxypropyl)glutathione (III), 1,3-di(S-glutathionyl)propan-2-ol (IV), and 1-(glycyl-S-cysteinyl)-3- (S-glutathionyl)propan-2-ol (V). The mechanisms of conjugate formation were addressed by assessing deuterium retention in conjugates derived from [1,1,2,3,3-2H5] DBCP (D5-DBCP). GSH conjugates I, III, IV, and V displayed quantitative retention of deuterium, an observation consistent with the formation of an episulfonium ion intermediate. GSH conjugate IIA, however, retained three atoms of deuterium, thus invoking a P-450 mechanism in its genesis. The involvement of glutathione transferase (GST) and sequential episulfonium ion intermediates in the formation of metabolites I, III, and IV was demonstrated in vitro. Upon incubation of DBCP with GST, metabolites I, III, and IV were identified by tandem mass spectrometry and were found to arise with quantitative retention of deuterium when D5-DBCP was employed as a substrate. An additional GSH conjugate, 1,2,3-tri(S-glutathionyl)propane (VI), was observed as the major metabolite in incubations of GST with DBCP. When the incubations of DBCP with GST were performed in H2(18)O, metabolite I incorporated two atoms of 18O, and metabolites III and IV incorporated one atom of 18O. The ability of GST to catalyze the formation of the four GSH conjugates observed in vivo, with quantitative retention of deuterium and incorporation of 18O from H2(18)O, may be rationalized by a mechanism invoking the initial formation of S-(2-bromo-3-chloropropyl)glutathione. Rearrangement of this unstable conjugate via several reactive episulfonium ions, with either hydrolysis by water or alkylation of GSH at various stages, would account for the pattern of metabolites and their status of isotopic enrichment observed under various incubation conditions.(ABSTRACT TRUNCATED AT 400 WORDS)     

Experimental mild increase in testicular temperature has drastic,but reversible,effect on sperm aneuploidy in men: A pilot study

In mammals testicular and epididymal temperature increase impairs spermatogenesis. This experimental study investigates the effects of a mild testis temperature increase (i.e. testis temperature remains below core body temperature) on sperm aneuploidy in men. In 5 fertile volunteers a testicular temperature increase was induced by maintaining the testes at suprascrotal position using specially designed underwear for 15 ± 1 h daily for 120 consecutive days. After heating men were followed for next 180 days. A control group (27 men) was recruited. Semen samples were collected before, during and after heating period and analyzed for chromosomes X, Y and 18 for aneuploidy using FISH. A total of 234,038 spermatozoa were studied by FISH. At day 34 of heating, mean sperm aneuploidy values were not modified. From day 34 of heating until day 45 post heating, FISH evaluation was not possible due to the drastic fall of sperm count. At day 45 post-heating total sperm aneuploidy percentage was twice higher than before heating whereas. Sex disomy (sperm XY18), sex chromosome nullisomy (sperm 18) were significantly higher than controls. These effects were completely reversed at 180 days post heat exposure. Conclusion: A mild rise in testicular temperature significantly increases sperm aneuploidies, reflecting an effect on the meiosis stage of spermatogenesis. The effect of heating was reversible and suggests that recovery of aneuploidy to normal values requires at least two cycles of spermatogenesis. Nonetheless, the low number of volunteers was a limitation of this pilot study and warrants further research on larger population.     

Time Course for Onset and Recovery from Effects of a Novel Male Reproductive Toxicant: Implications for Apical Preclinical Study Designs

In the pharmaceutic ICH S5(R2) guidelines for reproductive toxicity testing, a premating dose duration of 14 days is considered sufficient for assessment of male fertility for compounds that are not testicular toxicants. A novel α7 subtype of nicotinic acetylcholine receptor (α7nAChR) agonist, originally intended for treatment of Alzheimer's disease, did not cause changes in sperm counts, motility, or testicular histopathology in rat toxicity studies of up to 6 months duration. However, profound decrements in male fertility (reduced pregnancy rates and litter sizes) occurred after 11 weeks of dosing in male rats. In two time‐course investigations, dosed male rats were paired with undosed females after 5, 14, and 28 daily doses and again after 2 and 4 weeks off‐dose. Effects on male fertility were undetectable after 5 days. After 14 days, there was no effect on pregnancy rate, but preimplantation losses were increased. Effects on both pregnancy rates and preimplantation losses were clearly detectable after 28 days, but were of lesser magnitude than after 11 weeks of dosing. Fertility recovered rapidly after dose cessation. These studies illustrate the sensitivity of a long premating dose period at revealing hazard and determining the magnitude of effect on male fertility for compounds that are intended for chronic administration and do not affect testicular histopathology     

Testicular and epididymal function during the peripuberal period in Brahman bulls receiving various amounts of protein degradable in the rumen

Thirty-nine Brahman bulls with an initial age and weight of 301.7 +/- 4.1 d and 202.7 +/- 4.7 kg, respectively, were randomly allocated to 1 of 2 dietary treatment groups within age, weight and sire in order to study the influence of source of protein and stage of peripuberal period on testicular and epididymal function. In the soybean meal treatment the amount of protein undegradable in the rumen averaged 47%, while it was 72% in the fish meal treatment. The supplements were isocaloric and isonitrogenous. Bulls were electroejaculated, and castrations were performed randomly in a predetermined order when the first ejaculate with the first motile sperm cells (Stage 1), 10 to 25 million (Stage 2), and 50 million or more sperm cells (Stage 3 - puberty) was obtained. Testicular and epididymal traits were analyzed for a single testicle and epididymis. Daily sperm production, daily sperm production per gram of testicular parenchyma, testicular weight and testicular parenchyma weight were not affected by treatment. Bulls receiving fish meal had heavier (P < 0.01) epididymis than soybean meal-fed bulls (6.6 +/- 1.0 vs 3.9 +/- 0.6 g) but similar (P > 0.05) epididymal sperm reserves. Daily sperm production (1 testicle) was 115.2 +/- 0.1, 447.4 +/- 0.1, 792.7 +/- 0.1 million sperm cells, and daily sperm production per gram of testicular parenchyma was 1.5 +/- 0.5, 3.2 +/- 0.6 and 6.4 +/- 0.6 million sperm cells for bulls at Stage 1, 2 and 3, respectively. Sire and amount of undegradable intake protein had significant (P < 0.05) affects on the distribution of epididymal sperm reserves, with soybean meal-fed bulls having the higher proportions of epididymal sperm reserves in the cauda epididymis.     

Ameliorative Effect of Carvacrol on Cisplatin‐Induced Reproductive Damage in Male Rats

Cisplatin (CP) treatment causes the damage in male reproductive system. Carvacrol (CARV) is an antioxidant that is naturally found in some plants. We aimed to investigate the effect of CARV on CP‐induced reproductive toxicity in male rats. Eighteen adult male Sprague–Dawley rats were used. The control group (n = 6) was treated orally with physiological saline (PS) daily for 14 days and a single intraperitoneal (IP) PS injection on day 10. The CP group (n = 6) was administered with daily oral PS for 14 days and a single IP injection of 10 mg/kg CP on day 10. The CARV + CP group (n = 6) was treated with daily 75 mg/kg oral CARV for 14 days and a single IP injection of 10 mg/kg CP on day 10. CP treatment caused the damage on some spermatological parameters (motility, live sperm rate, and abnormal sperm rate), increased the oxidative stress, and induced testicular degeneration and apoptosis. However, CARV treatment mitigates CP‐induced reproductive toxicity.     

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.     

Testicular creatine and urinary creatine-creatinine profiles in mice after the administration of the reproductive toxicant methoxyacetic acid

It was previously observed that the acute or subchronic administration of some testicular toxicants, caused a significant raise in urinary creatine in rats. The aim of this study was to verify whether creatinuria could be detected in mice (a species with a different excretion profile of creatine) and whether it could be correlated to the levels of creatine in testis and to other parameters of testicular toxicity. The well known testicular toxicant methoxyacetic acid (MAA) was orally administered as a single dose (400 or 600 mg kg^-) to male adult mice B6C3F1. Twenty-four hours after dosing, urinary creatine and creatinine showed a significant reduction with respect to the pre-treatment values. At the following times post-dosing (48 and 72 h) the creatine exceeded the control and pre-treatment values, while creatinine had not yet recovered. The ratio creatine/creatinine was significantly higher than control and pre-treatment values, at 24 and 48 h after the treatments. In testis a significant, dose-dependent, decrease of creatine was observed 24 h after dosing, with a pattern related to the histopathologic alterations observed at different times after the treatments. Creatine determination was the earlier quantitative parameter of testicular toxicity, since at this time testis weights, sperm head number and enzyme activities (LDH-C4, SDH) were less affected, their maximum decrease being reached at 14 days after the treatments. These data suggest that in mice, 2-MAA could interfere with the metabolism of creatine, both in testis and other biosynthetically active tissues.     

4-Vinylcyclohexene diepoxide disrupts sperm characteristics,endocrine balance and redox status in testes and epididymis of rats

Objectives: Exposure to 4-vinylcyclohexene diepoxide (VCD) was reported to induce testicular germ cell toxicity in rodents. However, there is paucity of information on the precise biochemical and molecular mechanisms of VCD-induced male reproductive toxicity.

Methodology: This study investigated the influence of VCD on testicular and epidydimal functions following oral exposure of Wistar rats to VCD at 0, 100, 250 and 500?mg/kg for 28 consecutive days.

Results: Administration of VCD significantly decreased the body weight gain and organo-somatic indices of the testes and epididymis. When compared with the control, VCD significantly decreased superoxide dismutase and catalase activities in the testes whereas it significantly decreased superoxide dismutase activity but increased catalase activity in the epididymis. Moreover, while glutathione peroxidase activity and glutathione level remain unaffected, exposure of rats to VCD significantly increased glutathione S-transferase activity as well as hydrogen peroxide and malondialdehyde levels in testes and epididymis of the treated rats. The spermiogram of VCD-treated rats showed significant decrease in epididymal sperm count, sperm progressive motility, testicular sperm number and daily sperm production when compared with the control. Administration of VCD significantly decreased circulatory concentrations of follicle-stimulating hormone, luteinizing hormone and testosterone along with testicular and epididymal degeneration in the treated rats. Immunohistochemical analysis showed significantly increased cyclooxygenase-2, inducible nitric oxide synthase, caspase-9 and caspase-3 protein expressions in the testes of VCD-treated rats.

Conclusion: Exposure to VCD induces testicular and epidydimal dysfunctions via endocrine suppression, disruption of antioxidant enzymes activities, increase in biomarkers of oxidative stress, inflammation and apoptosis in rats.