Testicular toxicity and infertility in male rats treated with 1,3-dinitrobenzene

Weanling male Sprague-Dawley rats were gavaged 5 d/wk with 1,3-dinitrobenzene (m-DNB) at dosages of 0, 0.75, 1.5, 3.0, and 6.0 mg/kg X d. Males were bred to untreated females during treatment wk 10 and were killed during treatment wk 12. Although males dosed with 3 mg/kg X d inseminated the females and evidence of mating was observed in males dosed with 6 mg/kg X d, none of the males in these groups sired litters. Diminished sperm production (reduced testicular sperm head counts), decreased cauda epididymal sperm reserves, nonmotile spermatozoa, atypical sperm morphology, decreased weights of the testes and epididymides, seminiferous tubular atrophy, and incomplete spermatogenesis were also observed in these groups. Sperm production was also decreased in males dosed with 1.5 mg/kg X d. Changes in the spleen included increased weight at dosages of 1.5 mg/kg X d or higher and splenic hemosiderosis, which ranged from slight in rats treated with 0.75 mg/kg X d to moderately severe in those dosed with 6 mg/kg X d. The data indicate that m-DNB is a potent testicular toxicant in the male rat, capable of producing extensive damage to reproductive tissues and reproductive failure. Limited data on four rats that received 6 mg/kg X d and were allowed a 5-mo posttreatment recovery period suggested that the testicular effects are at least partially reversible.     

Reproductive toxicity of DDT in adult male rats.

The reproductive toxicity of DDT was investigated in adult male rats exposed to 50 and 100 mg/kg body weight (b.wt) day(-1) for 10 successive days. Compared with control animals, administration of DDT led to a dose-dependent reduction of testicular weight and the number as well as the percentage of motile spermatozoa in the epididymis. Testicular histological observations revealed also a marked loss of gametes in the lumen of seminiferous tubules. In DDT-treated rats, the seminal vesicles weights dropped significantly, resulting from a decrease of testosterone production by testes, whereas serum LH and FSH increased after pesticide exposure. This increase of gonadotrophin levels may be related to an impairment of the negative feedback exerted by the steroid on the hypothalamic--pituitary axis. It is concluded that DDT induced adverse effects on male rat fertility by acting directly on the testes and altering the neuroendocrine function.     

Reproductive toxicity of acrylamide-treated male rats

Acrylamide content is elevated in fried, baked and heat-processed starchy foods. The present experiment was conducted to investigate the reproductive toxicity of oral acrylamide in male rats. Thirty weaned SD male rats of 21-day-old were randomly allotted to three groups, and acrylamide was administered to each group at doses of 0, 5 and 10 mg/kg-d for 8 consecutive weeks. The results indicated that the growth of rats treated with acrylamide was retarded (P < 0.05), but relative weights of testes and epididymides compared to body weight were not significantly different (P > 0.05). Our results also indicate that the epididymal sperm reserves decreased significantly (P < 0.05), suggesting partial depletion of germ cells. In addition, histopathologic lesions were also present in the testes of treated rats. Furthermore, distinct expression patterns of sGC heterodimers were observed in this animal model. This may suggest different physiologic roles for sGC subunits in spermiogenesis and steroidogenesis.     

Reproductive toxicity of sodium valproate in male rats

Objectives:

To assess the effects of sodium valproate on rat sperm morphology, sperm count, motility, and histopathological changes in testis.

Materials and Methods:

Male Wistar rats (12 week old) were treated with sodium valpraote and sacrificed at the end of 2^nd, 4^th, 5^th, 7^th, 10^th and 15^th week after the last exposure to sodium valproate. Epididymal sperm count, sperm motility, sperm morphology, and histopathology of testes were analyzed.

Results:

Sperm count and sperm motility were decreased significantly by sodium valproate. The percentage of abnormal sperms increased in a dose-dependent manner. A histopathological study revealed that sodium valproate had caused sloughing of epithelial cells in testes.

Conclusion:

Sodium valproate causes reversible change in sperm motility, sperm count, morphology, and cytoarchitecture of testes.     

Preliminary investigations into the involvement of the intestinal microflora in CNS toxicity induced by 1,3-dinitrobenzene in male F-344 rats

Administration of a single oral dose of 20 mg/kg of 1,3-dinitrobenzene caused ataxia in germ-free male F-344 rats but not in conventional rats. Repeated oral dosing of 20 mg/kg, 1,3-DNB was required to cause ataxia in conventional rats. Considerable differences were observed between the uptake, tissue distribution and excretion of DNB in germ-free and conventional rats.     

Molecular mechanism on the testicular toxicity of 1,3-dinitrobenzene in Sprague-Dawley rats: preliminary study

The present study was conducted to elucidate the possible molecular mechanism of germinal cell apoptosis induced by Sertoli cell damage after 1,3-dinitrobenzene (1,3-DNB), a testicular toxicant, was administered to laboratory male rats. In this study, male Sprague-Dawley rats were administered with a single oral dose of 1,3-DNB (25 mg/kg body weight). Histopathological examinations and TUNEL methods revealed a marked increase in the number of apoptotic pachytene spermatocytes in seminiferous tubules showing stages VII–VIII and IX–XI of the spermatogenic cycle at 24 h after 1,3-DNB treatment. In immunohistochemical analysis, the cytoplasm and nuclei of pachytene spermatocytes were sometimes stained with antibodies to Bax and cleaved caspase-3 at 24 h after treatment. RT-PCR analysis for apoptosis-related gene expression showed that the expression of Bax,Bcl-2, Bcl-xL, and Bcl-xs genes, which are implicated in mitochondrial pathway, was significantly upregulated in the testes of the treated rats. These results suggest that the mitochondrial pathway is mainly involved in the testicular germinal cell apoptosis in rats induced by 1,3-DNB.     

Reproductive and developmental toxicity of inhaled 2,3-dichloro-1,3-butadiene in rats

Inhalation developmental and reproductive toxicity studies were conducted with 2,3-dichloro-1,3-butadiene (DCBD), a monomer used in the production of synthetic rubber. In the reproductive toxicity study, Crl:CD^®(SD)IGS BR rats (24/sex/group) were exposed whole body by inhalation to 0, 1, 5, or 50 ppm DCBD (6 h/day) for approximately 10–11 weeks total, through premating (8 weeks; 5 days/week), cohabitation of mating pairs (up to 2 weeks, 7 days/week), post-cohabitation for males (7 days) and from conception to implantation (gestation days 0–7 [GD 0–7]), followed by a recovery period (GD 8–21) for presumed pregnant females. Estrous cyclicity was evaluated during premating (last 3 weeks) and cohabitation. Reproductive organs and potential target organs, sperm parameters, and GD 21 fetuses (viability, weight, external alterations) were evaluated. In the developmental study, pregnant Crl:CD^®(SD)IGS BR rats (22/group) were exposed whole body by inhalation to 0, 1, 10, or 50 ppm DCBD (6 h/day) on GD 6–20; dams were necropsied on GD 21 (gross post-mortem only) and fetuses were evaluated (viability, weight, and external, visceral and skeletal exams). During the in-life portion of the studies, body weight, food consumption, and clinical observation data were collected. At 50 ppm, gasping and labored breathing occurred in both studies during the first few exposures; body weight and food consumption parameters were affected in parental animals from both studies, but were more severely affected in the developmental study. Fetal weight was decreased in the developmental study at 50 ppm. Degeneration of the nasal olfactory epithelium was observed in the reproduction study at 50 ppm. There were no effects on reproductive function, embryo–fetal viability, or increases in fetal structural alterations in either study. The no-observed-adverse-effect level (NOAEL) for reproductive toxicity was 50 ppm. The NOAEL for systemic toxicity in the reproduction study was 5 ppm based on adverse effects on body weight and food consumption parameters and nasal olfactory epithelial toxicity at 50 ppm in parental rats. The NOAEL for maternal and developmental toxicity was 10 ppm based on reduced maternal weight gain and food consumption and reduced fetal weight at 50 ppm in the developmental toxicity study.     

Reproductive toxicity of theobromine and cocoa extract in male rats.

The toxicities of theobromine and cocoa extract on the reproductive tract of male rats were compared in the present study. A cocoa powder extract containing 117 mg theobromine/g extract was prepared using 85% boiling methanol. Sprague-Dawley rats were weighed and dosed daily for 31 days with vehicle, 250 mg/kg theobromine, 2.14 g/kg cocoa extract (117 mg theobromine/g extract), or 0.43 g/kg cocoa extract by oral gavage. The animals were sacrificed on day 32. One testis and epididymis were removed and weighed. The epididymis was saved for the determination of epididymal sperm reserves. The remaining testis was fixed by whole body glutaraldehyde perfusion and processed for morphologic examination. A decrease in body weight gain and epididymal weights were observed in theobromine and high-dose cocoa-extract-treated groups. Theobromine and high-dose cocoa extract caused vacuolation within the Sertoli cell, abnormally shaped spermatids, and failed release of late spermatids in treated animals. Most of the vacuolations were found in the earlier and middle stage seminiferous tubules (stages I to VIII). However, the frequency of some parameters of testis alterations were significantly lower in the high-dose cocoa-extract-treated group compared to the theobromine-treated group. These data demonstrate the ability of a cocoa extract containing theobromine to alter testis structure in a similar pattern but with reduced intensity compared to that observed after oral exposure to pure theobromine.     

Reproductive toxicity associated with acrylamide treatment in male and female rats

The present study was designed to evaluate the influence of acrylamide (ACR) on male and female reproductive function. Male rats received ACR in drinking water (50, 100, or 200 ppm) for up to 10 wk. Copulatory behavior, semen, and (for controls and 100 ppm only) fertility and fetal outcomes were evaluated. Females received ACR (25, 50, 100 ppm) for 2 wk prior to initiation of breeding and then throughout gestation and lactation. Hindlimb splaying was apparent in the 200-ppm males by wk 4; less severe splaying appeared in the 100-ppm group at wk 8. Disruptions in copulatory behavior preceded the appearance of this ataxia. These disruptions in mating performance interfered with ejaculatory processes and subsequent transport of sperm, since semen was found in the uterus of only 1 of the 15 females mated with the 100-ppm males at wk 9. Moreover, only 33% of the females mated (wk 10) to the 100-ppm males were pregnant. Postimplantation loss was also significantly increased in this group. Hindlimb splaying appeared in the females receiving 100 ppm ACR during wk 1-2 of pregnancy. Body weight and fluid intake were also depressed. Dams in the 50-ppm group showed depression in these parameters during the last 2 wk of lactation. ACR did not significantly affect mating performance of the females, pregnancy rates, litter size, or survival. However, ACR did significantly depress pup body weight at birth (100-ppm group) and weight gain during lactation through post-weaning, d 42 (50- and 100-ppm groups). Vaginal patency was delayed in the 100-ppm group only.     

Clenbuterol toxicity in a young male athlete

Clenbuterol is a long-acting β-agonist that has several pharmacologic actions. In the past, it was misused mainly by bodybuilders and athletes to enhance their performances due to its lipolytic and muscle-enhancing effects. Today, its use has spread among recreation athletes as a weight loss agent. Since toxicity following clenbuterol is a rarely reported syndrome, we present a case of acute toxicity resulting in symptoms of sympathetic activation with haemodynamic instability and ECG signs of myocardial damage. A 34-years-old male, active local football player with no previous medical history, presented at our Emergency Unit with severe chest pain and shortness of breath. He was agitated, tachycardic and hypotensive, there were signs of myocardial damage on ECG. On admission, cardiac enzyme levels were normal [Troponin-T (TnT) 0.02?mcg/l] but started to rise soon afterwards (TnT 0.145?mcg/l), hypotension persisted and pain was worsening. The patient was managed with supportive care, he was given fluids, morphine, midazolam, sodium bicarbonate and vasopressor support. No invasive procedures were needed. He was discharged painless, with normal ECG and laboratory tests after 4 days. As abuse of weight loosing agents and anabolic substances is spreading rapidly, it should be always considered in young patients presenting with sympathomimetic features.     

Four-week intravenous repeated dose toxicity study of L-cysteine in male rats

A 4-week intravenous repeated dose toxicity study of L-cysteine (L-Cys) was conducted in male Sprague-Dawley rats to investigate in detail the toxic effects of this compound and to determine the dose level at which these toxic effects are observed following repeated intravenous administration. Male rats were randomly allocated to 4 groups to receive L-Cys by intravenous administration at dosages of 0, 100, 300, and 1,000 mg/kg body weight/day. Body weight gain was significantly suppressed throughout the study period in the 1,000-mg/kg group, although food consumption was reduced only on study day 3. A decrease in spontaneous activity, salivation, stereotypy, ptosis, and tremor were observed in the 1,000-mg/kg group. Mild anemia characterized by decreases in hemoglobin, hematocrit, mean corpuscular volume, mean corpuscular hemoglobin and an increase in the reticulocyte count was also noted in the 1,000-mg/kg group. Histopathological examination showed sperm granulomas in the epididymis and necrosis of the Purkinje cells and granular layer in the cerebellum in the 1,000-mg/kg group. Slight tubular basophilia with blood or hyaline casts was observed in the kidney in the 300-mg/kg and 1,000-mg/kg groups, associated with proteinuria or occult blood in urinalysis. Additional studies are needed to clarify the causes for these toxicological findings by excess of L-Cys.     

Age-dependent toxicity of acorn extract in young and old male rats

Intraperitoneal administration of acorn extract of dosage levels of 200, 400 and 600 mg/kg body weight did not produce significant change in the hepatic microsomal cytochrome P-450 levels and the activities of NADPH-cytochrome c reductase, benzphetamine N-demethylase and aniline hydroxylase in young, adult rats (weighing 200-250 g), with the exception of the activity of benzphetamine N-demethylase at the 600 mg/kg dose which was decreased significantly. On the other hand, a dose of only 100 mg/kg body weight ip to old rats (weighing 400-450 g) caused significant decreases in the microsomal cytochrome P-450, benzphetamine N-demethylase and NADPH-cytochrome c reductase activities. However, there was no significant change in the activity of aniline hydroxylase in these rats, indicating selective inhibition of the microsomal enzymes and higher susceptibility of old rats than young ones to acorn toxicants. When the serum samples from the treated young rats were analyzed for sorbitol dehydrogenase (SDH), alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activities as markers of liver toxicity, these activities were significantly higher in the treated rats than the corresponding control values. Similar changes were noted for old rats receiving a dose of 100 mg/kg body weight of acorn extract. The results indicate that acorn extract affects old rats more than young rats as measured by its effect on liver and liver microsomal enzymes.     

Reproductive toxicity assessment of chronic dietary exposure to soy isoflavones in male rats

Epidemiologic and experimental data suggest that consumption of diets that are rich in isoflavones may decrease cancer risk in the breast, prostate, and other tissues. Isoflavones such as genistein and daidzein are structurally similar to endogenous estrogens, and demonstrate both estrogenic and weak anti-estrogenic activities; these activities may underlie the impaired fertility and reproductive tract disorders reported in animals exposed to high doses of isoflavones. To identify possible effects of isoflavones on male fertility, we evaluated reproductive parameters in Wistar-Unilever rats receiving dietary exposure to PTI G-2535, a characterized mixture of soy-derived isoflavones containing 45% genistein, 23% daidzein, and 4% glycitein. Beginning at 10 weeks of age, rats received chronic dietary exposure to the soy isoflavone mixture (200 or 2000 mg/kg diet) for a minimum of 12 months. Controls received unsupplemented chow diet only for the same period. Dietary exposure to isoflavones induced no gross toxicity or alterations in body weight gain. Absolute and relative weights of the testis and epididymis in groups receiving high or low doses of isoflavones were comparable to those of controls, and histopathologic evaluations demonstrated that testicular morphology was similar in all study groups. Isoflavone exposure had no significant effects on spermatid count, sperm production, or sperm morphology in any group. These data suggest that the reproductive system of adult male rats is relatively insensitive to isoflavone toxicity at dose levels that demonstrate significant activity in cancer chemoprevention, and that male reproductive function is unlikely to be affected by long-term administration of isoflavones for cancer prevention or other purposes. The results of this study conducted in adult male rats differ from the significant alterations in reproductive parameters that have been reported in female rats receiving prenatal or juvenile exposure to isoflavones.     

低剂量毒死蜱重复染毒诱发雄性大鼠生殖毒性及其机制

目的探讨毒死蜱(CPF)低剂量重复染毒对雄性大鼠生殖功能的影响及其可能作用机制。方法健康雄性Wistar大鼠ig给予CPF 1,5和10 mg.kg-1,每日1次。连续染毒12周后取大鼠附睾和睾丸称重计算脏器系数,进行组织病理学、精子数量以及活力及畸形率等检查,测定睾丸碱性磷酸酶(AKP)、酸性磷酸酶(ACP)、γ-谷氨酰转肽酶(γ-GT)和乳酸脱氢酶(LDH)的活性;TUNEL法检测细胞凋亡,免疫组化及Western印迹法检测胱天蛋白酶和Fas,FasL蛋白的表达。结果与正常对照组相比,CPF染毒大鼠睾丸脏器系数显著升高,精子数及精子活力降低,精子畸形率显著升高(P<0.05),睾丸AKP和γ-GT活性抑制明显。组织病理检查显示,睾丸曲细精管疏松和生精细胞减少。CPF染毒组生精细胞凋亡增加(P<0.05)。Fas/FasL蛋白表达量升高。结论 CPF低剂量重复染毒能够诱导雄性大鼠生殖毒性,其作用机制可能与激活Fas/FasL受体途径而引起睾丸生精细胞凋亡有关。     

Reproductive effects of low acute doses of cadmium chloride in adult male rats

Adult male Sprague-Dawley rats were injected sc with cadmium (Cd, as cadmium chloride) in doses ranging from 1.6 to 152 mumol Cd/kg body weight (body wt). Fourteen days after dosing, animals were evaluated for reproductive damage. Evaluations for each animal included testes, seminal vesicles, and epididymides weights, vas deferens sperm concentration, and human chorionic gonadotropin (hCG)-stimulated serum testosterone concentration. Since 10 to 60% mortality occurred in the two highest dose groups (74 and 152 mumol/kg), no additional evaluations were conducted in these groups. The weights of the testes, seminal vesicles, and epididymides were reduced at least 40 to 50% in groups receiving 16 or 33 mumol Cd/kg while vas deferens sperm concentrations and hCG-stimulated serum testosterone concentrations were essentially zero. Significant depressions in the sperm concentrations and in the hCG-stimulated serum testosterone concentrations were found in animals receiving the two lowest doses (1.6 and 7.4 mumol Cd/kg) although no changes in tissue weights were observed in these animals. Curve-linear regression analyses for the dose responsiveness of these parameters demonstrated that serum testosterone concentration initially decreased at a rate of 19%/mumol Cd/kg, respectively, and was the most sensitive to Cd exposure. The initial rates of decrease for sperm concentrations and for seminal vesicles, testes, and epididymides weight were 6.45, 5.30, 4.19, and 2.45%/mumol Cd/kg, respectively, and were less responsive to Cd exposure than serum testosterone levels.     

Reproductive toxicity evaluation of vanadium in male mice

The reproductive toxicity of vanadium was studied in mice. Male Swiss mice were exposed to sodium metavanadate at doses of 0, 20, 40, 60, and 80 mg/kg per day given in the drinking water for 64 days. To evaluate the fertility of the vanadium-treated animals, males were mated with untreated females for 4 days. A significant decrease in the pregnancy rate was observed at 60 and 80 mg/kg per day of sodium metavanadate. However, metavanadate did not reduce fertility in male mt 20 and 40 mg/kg per day. Reproductive toxicity was measured by sperm count, sperm motility, organ weights, and histologic evaluation of the testes. Decreased body and epididymis weight was only observed in the 80 mg/kg per day group, while testicular weights were not altered by the treatment with all doses used. Sperm coung was significantly decreased at 40, 60, and 80 mg/kg per day, but the sperm motility was unaffected. Histopathological examination revealed that the testes were normal and that the epididymis of treated male mice contained normal appearing sperm. The no observed adverse effect level (NOAEL) was 40 mg/kg per day. Consequently, vanadium would not cause any adverse effect on fertility or testicular function in male mice at the concentrations usually ingested by humansthrough the diet and drinking water.     

Reproductive toxicity of methomyl insecticide in male rats and protective effect of folic acid

The acute toxicity (LD₅₀) of insecticide methomyl and its effects on male reproduction in rats were carried out. Methomyl was given orally to male rats daily for 65 successive days at two doses (0.5 and 1.0 mg kg⁻¹ b.wt., corresponding to 1/40 and 1/20 LD₅₀) alone and in combination with folic acid (1.1 mg kg⁻¹ b.wt., corresponding to acceptable daily intake, ADI). Fertility index, weight of sexual organs, semen picture, serum testosterone level and histopathology of testes were the parameters used to evaluate the reproductive efficiency of treated rats. The reversibility of methomyl effects was also studied after 65 days post-administration. The oral LD₅₀ of methomyl was 20.0 mg kg⁻¹ b.wt. in male rats. Methomyl significantly decreased the fertility index, weight of testes and accessory male sexual glands, serum testosterone level and sperm motility and count, but increased sperm cell abnormality. It induced testicular lesions characterized by moderate to severe degenerative changes of seminiferous tubules and incomplete arrest of spermatogenesis. These toxic effects were not persistent (reversible). Coadministration of folic acid with methomyl decreased its reproductive toxicity. A great attention should be taken during field application of methomyl to avoid its deleterious effects in farm animals and occupationally exposed humans.     

甲胺磷对雄性小鼠的生殖毒性

本文采用一组试验方法对有机磷杀虫剂甲胺磷的雄性小鼠生殖毒性进行研究。以0.2,0.8和3.2mg/kg ig染毒小鼠,观察到精子活动率下降、畸形精子增多、精子线粒体酶活性下降以及睾丸组织细胞结构改变,并呈剂量-反应关系。甲胺磷对雄性小鼠生殖细胞具有潜在诱变能力,并可通过多种途径干扰生精细胞的分化和代谢。建议中毒的育龄男子定期检产精液直至结果恢复正常方可生育后代。