Reproductive Development Of Male Offspring Research Articles

Exposure to manganese during sertoli cell formation and proliferation disturbs early testicular development in rats

Manganese (Mn) is a metal and important micronutrient. However, exposure to supraphysiological levels of Mn, which occur through fungicides, atmospheric emissions, drainages, and spills, has been related to health risks, including morphometric changes in the male reproductive organs and impairment on gametogenesis and sperm quality, impacting the fertile ability of adult animals. Despite the relevance of the fetal/perinatal period for toxicological studies on Mn, previous data only deal with the physical and neurological development of the offspring, without mentioning their reproductive development. The present study investigated whether exposure to Mn during fetal/perinatal phase, specifically during the period of formation and proliferation of Sertoli cells, impairs the reproductive development of male offspring in early postnatal life. Therefore, pregnant Wistar rats were randomly distributed into 3 experimental groups: Ctl (received saline solution), Mn-9 (received 9 mg/kg of MnCl2), and Mn-90 (received 90 mg/kg of MnCl2). The female rats received the experimental treatment by gavage from gestational day 13 to lactational day 15, i.e., postnatal day (PND) 15 of the pups. Oxidative damage to the genetic material of germ and Sertoli cells, together with a decrease in connexin 43 immunolabeling were observed in the testis of male pups evaluated at PND 15. In addition, an increase in the seminiferous tubules presenting slight epithelium vacuolization and cells with eosinophilic cytoplasm were observed, without apparent epididymal changes. In conclusion, it was demonstrated that Mn perturbed the initial testicular development by altering Sertoli cell integrity through oxidative insult, which may compromise the spermatogenesis in the long-term.

Sulfasalazine exposure during pregnancy and lactation: reproductive outcomes in male rat offspring.

Sulfasalazine (SAS) is a drug prescribed for pregnant and breastfeeding women with chronic inflammatory bowel diseases. SAS treatment induces transitory infertility in both adult men and male rats. Although SAS crosses the placenta and passes into maternal milk, the consequences of maternal SAS exposure on the reproductive development of male offspring needs further study. The current study evaluated whether maternal SAS exposure interferes with the reproductive development of male rat offspring in the neonatal, infant, pubertal and adulthood periods. Pregnant Wistar rats (n =10/group) received 300mg/kg/day of SAS dissolved in carboxymethyl cellulose (CMC), by gavage, from gestational day 0 to lactation day 21, and 3mg/kg/day of folic acid during gestation. The control group received CMC. During puberty, maternal SAS exposure increased the total length of seminiferous tubules, and round cells were observed in the lumen of caput and cauda epididymis. Moreover, SAS induced oxidative stress-related alterations in the testes of infant and adolescent rats. Although maternal SAS treatment caused reproductive alterations in infant and adolescent male rats, in adulthood, there were no impairments in sperm parameters that could compromise fertility. This study investigated the consequences of maternal exposure to SAS on the reproductive development of male rat offspring from birth to adulthood, employing a human-relevant dose. Thus, this study provides information for better understanding of SAS treatment during critical periods of development.

Perinatal exposure to known endocrine disrupters alters ovarian development and systemic steroid hormone profile in rats

Disrupted ovarian development induced by chemical exposure may impair fertility later in life. Since androgens are essential for early ovarian development, we speculated that perinatal exposure to a binary mixture of the known anti-androgens DEHP and procymidone could alter steroid synthesis, disrupt ovarian follicle recruitment and ultimately maturation in female rat offspring. Wistar rat dams were exposed by oral gavage from gestation day 7 to postnatatal day 22 to two mixture doses known to alter reproductive development in male offspring (low: 10 mg/kg bw/day of procymidone and 30 mg/kg bw/day of DEHP; high: 20 mg/kg bw/day of procymidone and 60 mg/kg bw/day of DEHP). The Effects on plasma steroid hormones, ovarian follicle distribution and expression of markers related to steroid synthesis were examined in female offspring. In prepubertal offspring, we observed an increased number of newly recruited (primary) follicles in exposed animals compared to controls, and the plasma steroid hormone profile was altered by exposure: levels of progesterone, corticosterone and estrone were dose dependently elevated, whereas androgen levels were unaffected. In adulthood, a trend towards a smaller number of early-stage follicles may point to accelerated loss of follicle reserves, which is disconcerting. The changes in follicle distribution in exposed ovaries may reflect the combined influence of androgen receptor antagonism and altered ovarian steroid synthesis. This study adds to a growing body of evidence showing altered ovarian development following exposure to human relevant chemicals with possible severe consequences for female fertility.

Impact of prenatal arsenic exposure on the testes and epididymides of prepubertal rats

Arsenic is a pollutant widely found in the environment due to natural and anthropogenic sources. Exposure to arsenic forms in drinking water has been related with male reproductive dysfunctions in humans and experimental animals at adult age. However, the impact of this pollutant on postnatal reproductive development of male offspring exposed in utero to arsenic is still unknown. Therefore, this study aimed to investigate the effects of prenatal arsenic exposure on the postnatal development of the testes and epididymides of rats, during prepuberty. For this purpose, pregnant female Wistar rats were provided drinking water containing 0 or 10 mg/L sodium arsenite (AsNaO2) from gestational day 1 (GD 1) until GD 21 and the male offspring was evaluated in different periods of prepuberty. Our results showed that prenatal arsenic exposure affected the initial sexual development of male pups, reducing their body weight and relative anogenital distance at postnatal day 1. At different periods of prepuberty, male pups from arsenic exposed dams showed a reduction of body and reproductive organs weights, testosterone levels and testis morphometric parameters. Moreover, these pups presented changes in the expression of SOD1, SOD2, CAT and GSTK1 genes and in the activity of superoxide dismutase, catalase and glutathione s-transferase in the testes and epididymides during prepuberty. Taken together, our results show that prenatal arsenic exposure provoked reproductive disorders in prepubertal male rats, probably due to reproductive reprograming and oxidative stress induced by this pollutant.

Prenatal exposure to residential PM2.5 and anogenital distance in infants at birth: A birth cohort study from Shanghai, China

Fine particulate matter (PM2.5) is believed to be one of the most hazardous air pollution with a ubiquitous presence. Animal studies have reported the association between prenatal exposure to traffic pollutant (not exclusively including PM2.5) and reproductive development in male offspring. However, the effects of prenatal exposure to PM2.5 on reproductive health in children are still unknown. The present study was based on the Shanghai-Minhang Birth Cohort Study (S-MBCS). A total of 876 pregnant women and their infants were included. Infants’ anogenital distance (AGD, the distance from the anus to the genitals; AGDap [anus-penis] and AGDas [anus-scrotum] for boys, and AGDac [anus-clitoris] and AGDaf [anus-fourchette] for girls) were measured at birth. PM2.5 concentrations during pregnancy were estimated using satellite based modeling approach. Multiple linear regression analysis and multiple informant model were conducted to examine the associations between prenatal exposure to PM2.5 (pre μg/m3) and offspring’s AGDs (mm). In order to minimize the misclassification of exposure, a sensitivity analysis restricted to mothers being off work during pregnancy was performed. In multiple linear regression models, we found that prenatal exposure to PM2.5 during the 1st and 3rd trimesters was associated with shorter AGDs. In multiple informant model, similar patterns were found, and statistically significant reductions were observed in AGDap (β=−0.278, 95%CI: -0.343∼-0.212), AGDac (β=−0.188, 95%CI: -0.247∼-0.130) and AGDaf (β= −0.163, 95%CI: -0.238∼-0.088) with PM2.5 exposure during the 1st trimester, and AGDap (β=−0.201, 95%CI: -0.247∼-0.155), AGDas (β=−0.158, 95%CI: -0.198∼-0.117), AGDac (β=−0.128, 95%CI: -0.167∼-0.089) and AGDaf (β = −0.144, 95%CI: -0.194∼-0.094) with PM2.5 exposure during the 3rd trimester. The sensitivity analysis restricted to women being off work during pregnancy showed similar results. PM2.5 exposure during the 1st and 3rd trimesters was associated with shortened AGDs in offspring at birth. Our findings provide preliminary evidence that prenatal exposure to PM2.5 might be associated with the reproductive development of offspring.

Glyphosate impairs male offspring reproductive development by disrupting gonadotropin expression

Sexual differentiation in the brain takes place from late gestation to the early postnatal days. This is dependent on the conversion of circulating testosterone into estradiol by the enzyme aromatase. The glyphosate was shown to alter aromatase activity and decrease serum testosterone concentrations. Thus, the aim of this study was to investigate the effect of gestational maternal glyphosate exposure (50 mg/kg, NOAEL for reproductive toxicity) on the reproductive development of male offspring. Sixty-day-old male rat offspring were evaluated for sexual behavior and partner preference; serum testosterone concentrations, estradiol, FSH and LH; the mRNA and protein content of LH and FSH; sperm production and the morphology of the seminiferous epithelium; and the weight of the testes, epididymis and seminal vesicles. The growth, the weight and age at puberty of the animals were also recorded to evaluate the effect of the treatment. The most important findings were increases in sexual partner preference scores and the latency time to the first mount; testosterone and estradiol serum concentrations; the mRNA expression and protein content in the pituitary gland and the serum concentration of LH; sperm production and reserves; and the height of the germinal epithelium of seminiferous tubules. We also observed an early onset of puberty but no effect on the body growth in these animals. These results suggest that maternal exposure to glyphosate disturbed the masculinization process and promoted behavioral changes and histological and endocrine problems in reproductive parameters. These changes associated with the hypersecretion of androgens increased gonadal activity and sperm production.

Gestational atrazine exposure: Effects on male reproductive development and metabolite distribution in the dam, fetus, and neonate

Few studies have investigated the long-term effects of atrazine (ATR) following in utero exposure. We evaluated the effects of gestational exposure of Sprague Dawley dams to ATR (0, 1, 5, 20, or 100 mg/kg-d) on the reproductive development of male offspring. We also quantified the distribution of ATR and its chlorinated metabolites in maternal, fetal, and neonatal fluid and tissue samples following gestational and/or lactational exposure. Dose-dependent levels of chlorotriazines, primarily diamino-s-chlorotriazine, were present in most samples analyzed, including fetal tissue. In utero exposure to 1–20 mg/kg-d ATR did not alter testosterone production, the timing of puberty, play behavior, or other androgen-dependent endpoints of male offspring. Significant maternal toxicity and postnatal mortality were observed at 100 mg/kg-d. We conclude that, although levels of chlorotriazines within the fetus were considerable, gestational exposures of 1–20 mg/kg-d do not lead to alterations in the measures of male development examined in this study.

Maternal Smoking during Pregnancy Specifically Reduces Human Fetal Desert Hedgehog Gene Expression during Testis Development

Maternal cigarette smoking during gestation increases cryptorchidism and hypospadias and reduces testis size and fertility in sons by unknown mechanisms. The objective of the study was to determine whether maternal smoking is linked with changes in male human fetal endocrinology, testis gene expression, and liver concentrations of cigarette smoke chemicals. This was an observational study of the male fetus, comparing pregnancies during which the mothers either did or did not smoke. The study was conducted at the universities of Aberdeen, Glasgow, and Nottingham and Macaulay Institute (Aberdeen). Testes, blood, and livers were collected from 69 morphologically normal human male fetuses of women undergoing elective termination of normal second-trimester pregnancies. Testosterone, human chorionic gonadotropin, LH, and cotinine; expression of 30 reproductive/developmental genes; liver concentrations of 16 polycyclic aromatic hydrocarbons; and Leydig, Sertoli. and germ cell numbers were determined. There were no significant differences in fetal size, testis weight, cell numbers, seminiferous tubule diameter, or circulating LH and testosterone. Fetuses from smoking mothers had smoking range cotinine levels and liver concentrations of polycyclic aromatic hydrocarbons that were significant predictors of maternal smoking (P < 0.001). Only the Sertoli cell-specific gene, desert hedgehog (DHH), was significantly altered by maternal smoking (reduced 1.8-fold, P = 0.013). The consequences of reduced DHH signaling in men and mice are consistent with epidemiology for effects of gestational maternal smoking on sons. Given the absence of other observed effects of maternal smoking, we concluded that reduced DHH is part of a mechanism linking maternal gestational smoking with impaired reproductive development in male offspring.

Disruption of reproductive development in male rat offspring following in utero exposure to phthalate esters

Certain Phthalate esters have been shown to produce reproductive toxicity in male rodents with an age dependent sensitivity in effects with foetal animals being more sensitive than neonates which are in turn more sensitive than pubertal and adult animals. While the testicular effects of phthalates in rats have been known for more than 30 years, recent attention has been focused on the ability of these agents to produce effects on reproductive development in male offspring after in utero exposure. These esters and in particular di-butyl, di-(2-ethylhexyl) and butyl benzyl phthalates have been shown to produce a syndrome of reproductive abnormalities characterized by malformations of the epididymis, vas deferens, seminal vesicles, prostate, external genitalia (hypospadias), cryptorchidism and testicular injury together with permanent changes (feminization) in the retention of nipples/areolae (sexually dimorphic structures in rodents) and demasculinization of the growth of the perineum resulting in a reduced anogenital distance (AGD). Critical to the induction of these effects is a marked reduction in foetal testicular testosterone production at the critical window for the development of the reproductive tract normally under androgen control. A second Leydig cell product, insl3, is also significantly down regulated and is likely responsible for the cryptorchidism commonly seen in these phthalate-treated animals. The testosterone decrease is mediated by changes in gene expression of a number of enzymes and transport proteins involved in normal testosterone biosynthesis and transport in the foetal Leydig cell. Alterations in the foetal seminiferous cords are also noted after in utero phthalate treatment with the induction of multinucleate gonocytes that contribute to lowered spermatocyte numbers in postnatal animals. The phthalate syndrome of effects on reproductive development has parallels with the reported human testicular dysgenesis syndrome, although no cause and effect relationship exists after exposure of humans to phthalate esters. However humans are exposed to and produce the critical phthalate metabolites that have been detected in blood of the general population, in children and also human amniotic fluid.

14. Effects of a high maternal phytoestrogen diet on the reproductive development of male offspring

14. Effects of a high maternal phytoestrogen diet on the reproductive development of male offspring

The fungicide procymidone alters sexual differentiation in the male rat by acting as an androgen-receptor antagonist in vivo and in vitro.

Procymidone is a dicarboximide fungicide structurally related to the well-characterized fungicide vinclozolin. Vinclozolin metabolites bind to mammalian androgen receptors (AR) and act as AR antagonists, inhibiting androgen-dependent gene expression in vivo and in vitro by inhibiting AR-binding to DNA. The current study was designed to determine if procymidone acted as an AR antagonist in vitro and to describe the dosage levels of procymidone that alter sexual differentiation in vivo. In vitro, procymidone inhibited androgen from binding the human AR (hAR) in COS (monkey kidney) cells transfected with hAR at 3.16 microM. In vitro, procymidone acted as an androgen antagonist, inhibiting dihydrotestosterone (DHT)-induced transcriptional activation at 0.2 microM in CV-1 cells (cotransfected with the hAR and a MMTV-luciferase reporter gene). In vivo, maternal procymidone exposure at 0, 25, 50, 100, or 200 mg kg-1 day-1 during gestation and early lactation (gestational day 14 to postnatal day 3) altered reproductive development of male offspring at all dosage levels tested. Male offspring exhibited shortened anogenital distance (at 25 mg kg-1 day-1 and above), permanent nipples, reduced weight of several androgen-dependent tissues (levator ani and bulbocavernosus muscles, prostate, seminal vesicles, Cowper's gland and glans penis), and malformations (hypospadias, cleft phallus, exposed os penis, vaginal pouch, hydronephrosis, occasional hydroureter, epididymal granulomas, and ectopic, undescended testes). In addition, perinatal procymidone treatment had a marked effect on the histology of the lateral and ventral prostatic and seminal vesicular tissues of the offspring (at 50 mg kg-1 day-1 and above). These effects consisted of fibrosis, cellular infiltration, and epithelial hyperplasia. This constellation of effects is similar to that produced by perinatal exposure to vinclozolin. However, procymidone appears to be slightly less potent in inducing malformations than vinclozolin by a factor of about two. In summary, the antiandrogenic activity of procymidone was demonstrated in vivo and in vitro in cell lines transfected with hAR. Since the role of androgens in mammalian sexual differentiation is highly conserved, it is likely that humans would be adversely affected by procymidone in a predictable manner if the human fetus was exposed to sufficient levels during critical stages of intrauterine and neonatal life.

6-Methoxy-2-benzoxazolinone and photoperiod: prenatal and postnatal influences on reproductive development in prairie voles (Microtus ochrogaster ochrogaster)

The effects of photoperiod and 6-methoxy-2-benzoxazolinone (6-MBOA) on the gonadal development of prairie voles was studied when this plant compound was available to pups in utero, during nursing, or postweaning. In part 1, pregnant voles exposed to long or short day lengths were fed food in which 6-MBOA was present (50 μg of 6-MBOA/g food) or absent prior to the birth of their young; all of these dams received a diet that lacked 6-MBOA after the pups were born. Other females were fed food without 6-MBOA throughout pregnancy, but received one of the diets during lactation. Short days inhibited reproductive development in male offspring, affected pup survival, and enhanced pelage development. Postnatal exposure to 6-MBOA did not affect the reproductive function of males. In contrast, prenatal exposure to 6-MBOA accelerated reproductive development among short-day males. Prenatal exposure to 6-MBOA did not affect survival of short-day males, but reduced survival of long-day pups. Prenatal 6-MBOA treatment affected the sex ratio of pups that survived until weaning (13:21; male:female) and of pups that died prior to weaning (26:5). In contrast, photoperiod did not affect reproductive function in female voles. Although reproductive function appears to be uncoupled from photoperiodic regulation, female prairie voles processed photoperiodic information; pelage development was enhanced among short-day females. In part II, breeding pairs were exposed to long or short days and fed food devoid of 6-MBOA prior to the birth of the young. On the day of birth, and for the following 3 weeks, either 6-MBOA-free or 6-MBOA-enriehed food was provided. After weaning, pups received their parents type of food until autopsy 3 or 7 weeks later. Again, photoperiod affected male, but not female, reproductive function. No consistent pattern of results from postnatal exposure to 6-MBOA was discerned for either males or females. Acceleration of reproductive function among short-day males because of prenatal influences may, be involved in the rapid rate of sexual maturation observed prior to peak population densities of microtine rodents. Because males of this species induce females into estrus, male prairie voles may depend on environmental cues to regulate reproductive function, while females may respond only to males. The physiological and ecological implications of these data are discussed.