Impairment on sperm quality and fertility of adult rats after antiandrogen exposure during prepuberty

This study evaluated the effects of antiandrogen exposure during the prepubertal period on reproductive development and reproductive competence in adults. Male rats were divided into two groups: flutamide, receiving 25 mg/kg/day of flutamide by oral gavage and control, receiving vehicle daily. Dosing continued from PND 21 to 44, and animals were killed on PND 50 or PND 75-80. The epididymis, prostate, vas deferens and seminal vesicle weights were lower in Flutamide group on PND 50, while on PND 80 only seminal vesicle weight was reduced. Fertility assessed by IUI revealed a decrease in the fertility potential in the flutamide-treated adults. Flutamide accelerated sperm transit time through the epididymis, impairing sperm motility and storage. A quantitative analysis of the cauda sperm membrane proteome revealed a few significant changes in protein expression. Thus, exposure to flutamide during the prepubertal period compromises the function of the epididymis along with epididymal sperm quality at adulthood.     

Effects of in utero and lactational exposure to SbV on rat neurobehavioral development and fertility

Meglumine antimoniate (MA) is a pentavalent antimony drug used to treat leishmaniases. We investigated the neurobehavioral development, sexual maturation and fertility of the offspring of MA-treated rats. Dams were administered MA (0, 75, 150, 300 mg Sb^V/kg body wt/d, sc) from gestation day 0, throughout parturition and lactation, until weaning. At the highest dose, MA reduced the birth weight and the number of viable newborns. In the male offspring, MA did not impair development (somatic, reflex maturation, weight gain, puberty onset, open field test), sperm count, or reproductive performance. Except for a minor effect on body weight gain and vertical exploration in the open field, MA also did not affect the development of female offspring. Measurements of the Sb levels (ICP-MS) in the blood of MA-treated female rats and their offspring demonstrated that Sb is transferred to the fetuses via the placenta and to the suckling pups via milk.     

Neurodevelopmental consequences of gestational and lactational exposure to pyrethroids in rats

Indiscriminate use of pyrethroids has raised serious health related concerns, especially about their effects on children. The present study was designed to assess the developmental neurotoxicity of two pyrethroids; bifenthrin (BIF) and β‐cyfluthrin (CYF) administered at 1/15 of LD₅₀ in rats. Pregnant females were exposed to the test compounds orally throughout gestation and lactation periods. Neonates were weighed and sexed at birth and were observed for any gross abnormality. Growth, viability and weaning indices were calculated during the lactation period. Exposure to both the compounds did not alter the physical developmental parameters viz. eye opening, pinna detachment, and fur appearance. CYF significantly impaired growth and survivability of pups. Behavioral endpoints assessed in neonates (surface righting, pivoting, and negative geotaxis reflex) as well as adults (motor activity and motor coordination) exhibited marked effect of CYF treatment. Administration of BIF to pregnant dams impaired pivoting in neonates. Decreased locomotion in the open‐field and impaired rota‐rod performance were also witnessed in BIF‐exposed animals. Enhanced oxidative stress was seen in corpus striatum, cerebellum, and hippocampus regions of the brain; reduced catalase, superoxide dismutase, and glutathione peroxidase activities were measured in BIF and CYF treated weanlings. Acetylcholinesterase activity was also found to be lowered following administration of both compounds at PND 21. The present results suggest that exposure to pyrethroids during critical periods of growth can induce long term effects on the behavior of animals. © 2015 Wiley Periodicals, Inc. Environ Toxicol 31: 1761–1770, 2016.     

Neonatal exposure to Aroclor 1254: Effects on adult hepatic testosterone hydroxylase activities

1. The effects of neonatal exposure to Aroclor 1254 (100 μmol/kg) on the metabolism of testosterone by adult male and female rats were determined by comparing their hepatic microsomal testosterone hydroxylase activities at 60, 90 and 120 days after the initial exposure.

2. The most pronounced effects in male rats were observed 90 days after treatment with Aroclor 1254, whereas in female rats the major changes in testosterone hydroxylase activities were observed after 60 days.

3. Ninety-day-old male rats neonatally treated with Aroclor 1254 exhibited decreased basal testosterone 7α-hydroxylase and increased basal testosterone 16α-, 2α- and 15β-hydroxylase activities and androstenedione formation. In addition, the Aroclor 1254-mediated induction of testosterone 7α- and 6α-hydroxylase activities and androstenedione formation was decreased, and that of testosterone 2β- and 15β-hydroxylase activities was increased.

4. Sixty-day-old female rats exposed neonatally to Aroclor 1254 exhibited increased basal testosterone 16α-, 2β-, 6α- and 15β-hydroxylase activities and androstenedione formation, and increased Aroclor 1254-induced metabolism of testosterone at all positions except 16α and 2α.

5. Changes in testosterone hydroxylase activities indicative of permanent damage (or imprinting) in androgen metabolism, i.e. altered activities in 120-day-old animals, were observed only in male rats. These activities included basal testosterone 6β-, 16α- and 2α-hydroxylase activities and androstenedione formation.     

大鼠孕期和哺乳期接触硫丹对仔代雄性生殖系统发育的影响

成年雌性Wistar大鼠确定受孕后随机分为4组,每组8-10只,从整个孕期到哺乳期（到仔鼠出生后28 d止）持续给予硫丹0, 0.5, 1.0和2.5 mg·kg^-1·d^-1 po. 结果2.5 mg·kg^-1·d^-1组在孕后期出现明显的母体毒性,4/10孕鼠死亡,其他各组无孕鼠死亡.各组仔鼠雌雄性别比例无明显差别. 2.5 mg·kg^-1·d^-1组出生仔鼠体重略低于对照组,但以后逐渐恢复. 出生后28 d处死部分雄性仔鼠检查睾丸生殖细胞凋亡发生率,结果各组之间无明显差异. 各组雄性仔鼠均未发现隐睾或尿道下裂等畸形,肛门到生殖器间的距离与对照组比较亦无明显差别. 雄鼠成年后,睾丸,附睾,前列腺重量以及组织形态都无明显改变.每日精子生成数,附睾精子计数和精子畸形率以及生育力亦无明显影响. 说明在本试验条件下,大鼠孕期和哺乳期接触硫丹,没有引起子代雄性生殖系统结构的雌性化和生殖功能的明显改变. 结合硫丹对雌鼠子宫增殖亦无影响,认为硫丹在大鼠体内并没有明显的雌激素样作用.     

大鼠孕期和哺乳期接触硫丹对仔代雄性生殖系统发育的影响

成年雌性 Wistar大鼠确定受孕后随机分为 4组 ,每组 8- 1 0只 ,从整个孕期到哺乳期 (到仔鼠出生后 2 8d止 )持续给予硫丹 0 ,0 .5,1 .0和 2 .5mg· kg-1· d-1po.结果 2 .5mg· kg-1· d-1组在孕后期出现明显的母体毒性 ,4/1 0孕鼠死亡 ,其他各组无孕鼠死亡 .各组仔鼠雌雄性别比例无明显差别 .2 .5mg·kg-1·d-1组出生仔鼠体重略低于对照组 ,但以后逐渐恢复 .出生后 2 8d处死部分雄性仔鼠检查睾丸生殖细胞凋亡发生率 ,结果各组之间无明显差异 .各组雄性仔鼠均未发现隐睾或尿道下裂等畸形 ,肛门到生殖器间的距离与对照组比较亦无明显差别 .雄鼠成年后 ,睾丸 ,附睾 ,前列腺重量以及组织形态都无明显改变 .每日精子生成数 ,附睾精子计数和精子畸形率以及生育力亦无明显影响 .说明在本试验条件下 ,大鼠孕期和哺乳期接触硫丹 ,没有引起子代雄性生殖系统结构的雌性化和生殖功能的明显改变 .结合硫丹对雌鼠子宫增殖亦无影响 ,认为硫丹在大鼠体内并没有明显的雌激素样作用     

Effects of gestational and lactational exposure to organochlorine compounds on cellular, humoral, and innate immunity in swine.

Few studies have characterized the immunotoxic potential of complex mixtures of organochlorines (OCs) that bear environmental relevance. We monitored immune parameters in male piglets exposed in utero and through lactation to an OC mixture which was designed to approximate that found in the traditional diet of Arctic aboriginal populations. Prepubertal sows were administered orally either corn oil (control group) or the OC mixture in increasing doses (low, medium, and high). The sows were inseminated with the semen from an untreated boar and OC treatment was continued throughout gestation and lactation (21 days). Blood was collected from the sows at delivery and monthly from piglets until 8 months of age for the determination of plasma OC concentrations and parameters of innate, cellular, and humoral immunity. Treatment with the OC mixture had no dose-dependent effect on the proportion of CD4+ and CD8+ T-cell subsets, and did not modulate the functional activity of the complement component C2. The proportion of CD4+CD8+ cells, CD8+DR+ cells, and the mitogenic lymphoproliferative response increased in OC-treated, 4-month-old piglets. At 6 months, the lymphoproliferative response to mitogen and the proportion CD4+CD8+ cells were still elevated in the OC-treated piglets, but the proportion of CD8+DR+ cells was decreased as compared to the controls. Animals in the high-dose group also exhibited a slight increase in polymorphonuclear leukocyte phagocytic activity at 8 months of age. Furthermore, the high dose decreased the antibody response to Mycoplasma hyopneumoniae. Our results indicate that developmental exposure to an environmentally relevant OC mixture alters the immune function in swine.     

Gestational and lactational exposure to the polychlorinated biphenyl mixture Aroclor 1254 modulates retinoid homeostasis in rat offspring

Polychlorinated biphenyls (PCBs) induce a broad spectrum of biochemical and toxic effects in mammals including alterations of the vital retinoid (vitamin A) system. The aim of this study was to characterize alterations of tissue retinoid levels in rat offspring and their dams following gestational and lactational exposure to the PCB mixture Aroclor 1254 (A1254) and to assess the interrelationship of these changes with other established sensitive biochemical and toxicological endpoints. Sprague-Dawley rat dams were exposed orally to 0 or 15 mg/kg body weight/day of A1254 from gestational day 1 to postnatal day (PND) 23. Livers, kidneys and serum were collected from the offspring on PNDs 35, 77 and 350. Tissue and serum retinoid levels, hepatic cytochrome P450 (CYP) enzymes and serum thyroid hormones were analyzed. A multivariate regression between A1254 treatment, hepatic retinoid levels, hepatic CYP enzymes activities, thyroid hormone levels and body/liver weights was performed using an orthogonal partial least-squares (PLS) analysis. The contribution of dioxin-like (DL) components of A1254 to the observed effects was also estimated using the toxic equivalency (TEQ) concept. In both male and female offspring short-term alterations in tissue retinoid levels occurred at PND35, i.e. decreased levels of hepatic retinol and retinoic acid (RA) metabolite 9-cis-4-oxo-13,14-dihydro-RA with concurrent increases in hepatic and renal all-trans-RA levels. Long-term changes consisted of decreased hepatic retinyl palmitate and increased renal retinol levels that were apparent until PND350. Retinoid system alterations were associated with altered CYP enzyme activities and serum thyroid hormone levels as well as body and liver weights in both offspring and dams. The estimated DL activity was within an order of magnitude of the theoretical TEQ for different endpoints, indicating significant involvement of DL congeners in the observed effects. This study shows that tissue retinoid levels are affected both short- and long-term by developmental A1254 exposure and are associated with alterations of other established endpoints of toxicological concern.     

Does early exposure to maternal smoking affect future fertility in adult males?

Animal data suggest that prenatal exposure to certain tobacco smoke components such as nicotine may affect the development of the male gonadal axis, which may in turn affect future adult fertility. There are no previous epidemiologic studies on the potential effects of early (prenatal and childhood) exposure to maternal smoking on the reproductive system in adult male offspring. To investigate this question, we used data from a follow-up study of reproductive function and fertility among young adult sons of mothers who had participated in a randomized clinical trial of diethylstilbestrol use during pregnancy. We observed no significant effects of early exposure to maternal smoking on conventional semen characteristics, hormone levels (follicle stimulating hormone [FSH], luteinizing hormone [LH] and testosterone), urogenital abnormalities and diseases, or perceived infertility problems. Current active smoking by the men was, however, associated with a significant decrease in the percentage of sperm with normal morphology.     

Lead exposure reduces sperm quality and DNA integrity in mice

Toxicity of lead on male reproductive functions has raised wide public concern as environmental lead contamination remains common worldwide. Conflicting and controversial data are available regarding effects of lead on male fertility. More importantly, our knowledge on effects of lead on sperm DNA integrity is significantly limited. Thus, further studies should focus on this issue. In the current study, adult male mice were exposed to a series of lead acetate concentrations in drinking water for six weeks. Following administration, lead levels in blood, testicles, and epididymis were measured, and potential changes in morphology of testis and epididymis due to lead exposure were identified. We also analyzed sperm parameters, including sperm density, viability, motility, and morphology, to evaluate quality of sperm collected from epididymis. Especially, hypothetical influence of lead on sperm DNA integrity was also evaluated by terminal deoxynucleotidyltransferase‐mediated dUTP‐biotin nick end labeling, alkaline comet assay, and sperm chromatin structure assay. Lead exposure possibly exerted no effect on growth of mice because these animals acquired similar body weight gain during the experimental period. However, high lead concentrations (0.5% and 1%) in drinking water affected sperm motility and increased percentage of spermatozoa with abnormal morphology. In groups treated with 0.25%, 0.5%, and 1% lead acetate, percentages of sperm cells showing DNA breaks and chromatin structure damage significantly increased. Altogether, lead exposure not only exhibits adverse effects on sperm physiological parameters, but also impairs DNA structure and integrity. These effects may lead to significant decline in male fertility.     

Influence of in vitro exposure to mycotoxin zearalenone and its derivatives on swine sperm quality

Zearalenone (ZEA) is a fusariotoxin naturally occurring in crops with known estrogenic activity in swine, the most sensitive known species. The metabolism by swine of ZEA, principally into alpha-zearalenol (alpha-ZOL), is considered as a bio-activation because of its high affinity with estrogenic receptors. Discordant data on male reproductive failures induced by ZEA in vivo are described. In this study, we evaluated the effects to boar spermatozoa when they are exposed in vitro to ZEA and its derivatives (alpha-ZOL, beta-ZOL). We analyzed viability, apoptosis (terminal deoxynucleotidyltransferase dUTP nick end-labelling (TUNEL)), sperm chromatin stability (sperm chromatin structure assay (SCSA)) and motility (using computer-aided sperm analysis (CASA)). Each mycotoxin influenced a specific function of spermatic cells. alpha-Zearalenol and ZEA, at picomolar levels, negatively influenced chromatin structure stability and viability, respectively, whereas beta-ZOL negatively influenced the sperm motility at micromolar levels. This study is the first using these direct measures of sperm integrity to show the potential for an adverse effect of ZEA exposure on boar fertility.     

Gestational and pubertal exposure to low dose of di-(2-ethylhexyl) phthalate impairs sperm quality in adult mice

Di-(2-ethylhexyl)-phthalate (DEHP) is a compound widely used as a plasticizer, which can leach from plastics into the environment and thus influence human health. The aim of this study was to analyze whether exposure to an environmentally relevant dose of DEHP during mice fetal development or puberty can cause long-lasting changes detectable month/s after the last exposure. We used a DEHP concentration relevant to a daily human intake of 2.4–3 μg/kg of body weight/day. CD1 outbred mice were treated either in utero or postnatally during puberty and analyzed in adulthood. Analyzing fertility parameters using morphometric, histologic, genomic and proteomic methods we showed that DEHP exposure leads to decreased sperm concentration and quality, in both experimental groups. Moreover, the changes in anogenital distance, seminal vesicle weight, and testicular gene expression suggest a disturbance of androgen signaling in exposed animals. In conclusion, we hereby present, that the prenatal and pubertal exposure to a low dose of DEHP negatively influenced reproductive endpoints in male mice, and some of the effects were persistent until adulthood.     

盐酸西部曲明对小鼠生殖力和着床前后胚胎发育的影响

目的　评价减肥新药盐酸西部曲明对♀亲代动物的生殖毒性和受精卵着床前的发育毒性。方法　持续饮水内给药 ,♂小鼠交配前给药 8周并持续给药至交配成功处死之前 ;♀小鼠交配前给药 2周并持续给药至妊娠d6。设 32、2 83、0 .2 5mg·kg-1·d-13个剂量组及 1个阴性对照组 ,观察亲代动物的一般状况、交配、受孕和妊娠 ,胎仔的着床、存活、体长、体重、外观、内脏和骨骼畸形等检测指标。结果　除相当于人预期摄入量 12 8倍的高剂量引起了亲代雄鼠体重减轻外 ,亲代和子代小鼠均未见其他毒性反应。结论　未见盐酸西部曲明对亲代有生殖毒性和对子代有发育毒性。     

Effects of long-term exposure to manganese chloride on fertility of male and female mice

The effect of long-term ingestion of manganese (II) chloride tetrahydrate was investigated on fertility of male and female Swiss mice. Adult male or female mice ingested a solution of manganese chloride along with drinking water at concentrations of 1000, 2000, 4000 and 8000 mg/l for 12 weeks. Fertility was significantly reduced in male mice exposed to manganese chloride solution at a concentration of 8000 mg/l, but not at the other concentrations. There were no treatment-related effects on the number of implantation sites, viable fetuses or the number of resorptions in female rats impregnated by males who had ingested manganese chloride. Fertility was not significantly reduced in female mice exposed to manganese chloride solution at all concentrations used in this study. However, the numbers of implantations and viable fetuses were significantly reduced in females exposed to manganese chloride solution at a concentration of 8000 mg/l. There was no significant effect on the number of resorbed fetuses in females exposed to manganese chloride solution compared to their control counterparts. Absolute body weight was not significantly affected in females exposed to manganese chloride solutions. However, ovarian weight was significantly increased in females exposed to manganese chloride solution at concentrations of 4000 and 8000 mg/l. A significant increase in the uterine weight was also observed at all concentrations used in the study. These results indicate that ingestion of manganese chloride by adult male and female mice causes some adverse effects on fertility and reproduction.     

Neonatal exposure to Aroclor 1254: effects on adult hepatic testosterone hydroxylase activities

1. The effects of neonatal exposure to Aroclor 1254 (100 mumol/kg) on the metabolism of testosterone by adult male and female rats were determined by comparing their hepatic microsomal testosterone hydroxylase activities at 60, 90 and 120 days after the initial exposure. 2. The most pronounced effects in male rats were observed 90 days after treatment with Aroclor 1254, whereas in female rats the major changes in testosterone hydroxylase activities were observed after 60 days. 3. Ninety-day-old male rats neonatally treated with Aroclor 1254 exhibited decreased basal testosterone 7 alpha-hydroxylase and increased basal testosterone 16 alpha-, 2 alpha- and 15 beta-hydroxylase activities and androstenedione formation. In addition, the Aroclor 1254-mediated induction of testosterone 7 alpha- and 6 alpha-hydroxylase activities and androstenedione formation was decreased, and that of testosterone 2 beta- and 15 beta-hydroxylase activities was increased. 4. Sixty-day-old female rats exposed neonatally to Aroclor 1254 exhibited increased basal testosterone 16 alpha-, 2 beta-, 6 alpha- and 15 beta-hydroxylase activities and androstenedione formation, and increased Aroclor 1254-induced metabolism of testosterone at all positions except 16 alpha and 2 alpha. 5. Changes in testosterone hydroxylase activities indicative of permanent damage (or imprinting) in androgen metabolism, i.e. altered activities in 120-day-old animals, were observed only in male rats. These activities included basal testosterone 6 beta-, 16 alpha- and 2 alpha-hydroxylase activities and androstenedione formation.     

Perinatal exposure to low doses of tributyltin chloride reduces sperm count and quality in mice

Exposure to endocrine disruptors (EDs) during early development might lead to adverse health outcomes later in life. Tributyltin (TBT), a proven ED, is widely used in consumer goods and industrial products. Herein we demonstrate the effects of low doses of tributyltin chloride (TBTCl) on reproduction of male KM mice. Pregnant mice were administered by gavage with 0, 1, 10, or 100 μg TBTCl/kg body weight/day from day 6 of pregnancy through the period of lactation. TBTCl dramatically decreased sperm counts and motility on postnatal days (PNDs) 49 and 152. Meanwhile, a significant increase in sperm abnormality was observed in exposed mice on PND 49, but comparable to that in the control on PND 152. The histopathological analysis of testes of treated animals showed a dose‐dependent increase in sloughing of germ cells in seminiferous tubules. Mice treated with 10 μg TBTCl/kg exhibited decreased intratesticular 17β‐estradiol (E2) levels on PND 49, and then followed by an obvious recovery on PND 152. While, no significant differences in serum E2, testosterone (T) levels and intratesticular T levels were detectable between control and TBTCl‐exposed offspring at the sacrifice. These results suggest that perinatal TBTCl exposure is implicated in causing long lasting alterations in male reproductive system and these changes may persist far into adulthood. © 2013 Wiley Periodicals, Inc. Environ Toxicol 30: 44–52, 2015.     

In utero and lactational exposure to Aroclor 1254 affects bone geometry, mineral density and biomechanical properties of rat offspring

Exposure to polychlorinated biphenyls (PCBs) induce a broad spectrum of toxic effects in various organs including bone. The most susceptible age-groups to the toxic effects of PCBs are foetuses and infants. The aim of the present study was to quantitatively evaluate changes in bone geometry, mineral density and biomechanical properties following perinatal exposure to the PCB mixture, Aroclor 1254 (A1254), and to examine the persistence of observed bone alterations by following the offspring over time. Sprague-Dawley rat offspring were exposed to A1254 from gestational day 1 to post-natal day (PND) 23. Femur and tibia were collected on PNDs 35, 77 and 350 and were analyzed by peripheral quantitative computed tomography and biomechanical testing. At PND35, exposure to A1254 induced short, thin femur and tibia, with reduced mechanical strength of femoral neck. No treatment-related bone changes were detected in offspring at PND77 or PND350. In conclusion, the present investigation suggests that perinatal exposure to A1254 leads to shorter, thinner and weaker bones in juvenile rats at PND35, with these effects being absent at later time-points as exposure is discontinued. The results indicate that the observed bone effects are mainly driven by the dioxin-like congeners, although it cannot exclude the contribution of the non dioxin-like congeners to the exposure outcome.     

Effects of gestational and lactational exposure to low doses of PCBs 126 and 153 on anterior pituitary and gonadal hormones and on puberty in female goats

The aim of the present study was to investigate if environmental doses of PCB 153 and PCB 126 could produce effects in a controlled animal model. Possible adverse effects on the hypothalamic-pitutitary-gonadal axis were examined by measuring gonadotrophins and gonadal steroid hormone concentrations in goat kids exposed during gestation and lactation. The concentrations of PCB 153 and PCB 126 in adipose tissue in the goat kids 9 months post-partum were 5800 ng/g (fat-weight, range; 2900-12700 ng/g) and 0.49 ng/g (fat-weight, range; 0.28-0.80 ng/g), respectively. The pre- and post-pubertal plasma concentrations of luteinizing hormone (LH), follicle stimulating hormone (FSH), prolactin (Prl) and progesterone (P4) were analysed. LH, FSH, Prl, and P4 were also measured during an induced oestrus cycle. The prepubertal LH concentration was significantly lower, the puberty was delayed and the P4 level during the luteal phase of an estrous cycle was higher in the group exposed to PCB 153. No significant effect of PCB 153 exposure was found on Prl and FSH. PCB 126 did not produce any effects at the exposure level tested in this study. In conclusion, perinatal exposure to PCB 153 affected the reproductive function and the puberty maturation in goats.     

Decline of sperm quality and testicular function in male mice during chronic low-dose exposure to microcystin-LR

The effects of chronic low-dose exposure to microcystins were preliminarily studied on sperm quality and testicular function in male mice. Microcystin-LR (MC-LR) was orally administered to male mice at 0, 1, 3.2, and 10 μg/L for 3 and 6 months. Our preliminary study found in three-month group, sperm quality declined at 3.2 and 10 μg/L doses, testosterone dropped at 10 μg/L, levels of LH and FSH increased, and Leydig cells exhibited apoptosis. Similar, but more pronounced, effects were observed in groups treated with MC-LR for 6 months. Compared to control (0 μg/L), the rate of sperm abnormality was higher and testosterone levels were lower following administration of 3.2 and 10 μg/L MC-LR and structural damage to the testis was observed with 10 μg/L dose. Thus, chronic low-dose treatment with MC-LR results in substantial toxicity to male reproduction, causing declines in sperm quality, decreased levels of serum testosterone, and injury to the testis.