Spermatogenesis In Male Offspring Research Articles

Neonatal undernutrition induced by litter size expansion alters testicular parameters in adult Wistar rats.

Several models of maternal undernutrition reveal impairment of testicular development and compromise spermatogenesis in male offspring. The expansion of the litter size model, valuable for studying the impact of undernutrition on early development, has not yet been used to evaluate the consequences of early undernutrition in the adult male reproductive system. For this purpose, pups were raised in either normal litter (ten pups/dam) or large litter (LL; sixteen pups/dam). On postnatal day 90, sexual behaviour was evaluated or blood, adipose and reproductive tissues were collected for biochemical, histological and morphological analysis. Adult LL animals were lighter and thinner than controls. They showed increased food intake, but decrease of retroperitoneal white adipose tissue weight, glycaemia after oral glucose overload and plasma concentration of cholesterol. Reproductive organ weights were not altered by undernutrition, but histopathological analysis revealed an increased number of abnormal seminiferous tubules and number of immature spermatids in the tubular lumen of LL animals. These animals also showed reduction in total spermatic reserve and daily sperm production in the testes. Undernutrition decreased the number of Sertoli cells, and testosterone production was increased in the LL group. Mitochondrial activity of spermatozoa remained unchanged between experimental groups, suggesting no significant impact on the energy-related processes associated with sperm function. All animals from both experimental groups were considered sexually competent, with no significant difference in the parameters of sexual behaviour. We conclude that neonatal undernutrition induces histological and physiological testicular changes, without altering sperm quality and sexual behaviour of animals.

Environmentally relevant perinatal exposure to DBP accelerated spermatogenesis by promoting the glycolipid metabolism of Sertoli cells in male offspring mice

Since Sertoli cells (SCs) play an essential role in providing energy for spermatogenesis, the present study aimed to investigate the effects of maternal exposure to plasticizer Dibutyl phthalate (DBP) on the onset of spermatogenesis in male offspring through the metabolism pathway as well as the underlying molecular mechanism. Here, pregnant mice were treated with 0 (control), 50, 250, or 500 mg/kg/day DBP in 1 mL/kg corn oil administered daily by oral gavage from gestation day (GD) 12.5 to parturition. The in vivo results showed that 50 mg/kg/day DBP exposure could promote the expression of glucose metabolism-related proteins (GLUT3, LDHA, and MCT4) in the testis of 22 days male offspring. The in vitro results demonstrated that 0.1 mM monobutyl phthalate (MBP, the active metabolite of DBP) promoted the lactate production, glucose consumption, and glycolytic flux of immature SCs, which was paralleled by the upregulated expression of glucose metabolism-related proteins (GLUT1, GLUT3, LDHA, and MCT4). On the other hand, DBP/MBP increased fatty acid (FA) uptake, FA β-oxidation, and ATP production by promoting the expression of CD36 in immature SCs, which might accelerate the maturity of SCs to support the onset of spermatogenesis. Therefore, our findings provided a new perspective on glycolipid metabolism to explain prenatal DBP exposure leading to earlier onset of spermatogenesis in male offspring mice.

Parental exposure to 3-methylcholanthrene before gestation adversely affected the endocrine system and spermatogenesis in male F1 offspring

The compound 3-methylcholanthrene (3-MC) is an environmental pollutant belonging to the PAHs, which reportedly have the potential to disrupt the endocrine systems of animals. In the present study, 4-week-old male and female mice were given 3-MC through their diet at a dose of 0.5 mg/kg of chow for 6 weeks before pregnancy. The first filial (F1) generation offspring of exposed or unexposed parental mice were sacrificed at the age of 5 or 10 weeks (F1-5 W or F1-10 W), and the potential effects on the F0 and F1 offspring were evaluated. The results showed that the serum and testicular testosterone (T) levels and the genes involved in T synthesis in F0 males and male F1-5 W individuals born from female mice exposed to 3-MC were significantly decreased. In addition, histological analysis suggested that exposure to 3-MC significantly disrupted testicular morphology in F0 mice and in the offspring of female mice exposed to 3-MC. Further investigation revealed that genes involved in spermatogenesis, such as Phosphoglycerate kinase 2 (Pgk2), Glial cell derived neurotrophic factor (Gdnf), Myeloblastosis oncogene (Myb), DEAD box helicase 4 (Ddx4) and KIT proto-oncogene receptor tyrosine kinase (Kit), were suppressed in these mice. However, the adverse effects of parental 3-MC exposure on the adolescent mice were mitigated when they grew to adulthood, which was verified by studies on F1-10 W mice. Our results suggest that female exposure to 3-MC has the potential to disrupt the endocrine system and spermatogenesis in male offspring; nevertheless, the adverse effects might be mitigated with age.

Decreased Capacity for Sperm Production Induced by Perinatal Bisphenol A Exposure Is Associated with an Increased Inflammatory Response in the Offspring of C57BL/6 Male Mice.

Many previous studies have indicated the adverse effects of bisphenol A (BPA) on sperm production and quality; however, the mechanisms underlying BPA male reproductive toxicity have yet to be elucidated. The main purpose of this study was to investigate the effect of perinatal exposure to BPA on the spermatogenic capacity of male offspring, and to explore the possible influence of inflammatory responses in BPA reproductive toxicity. Twenty-one pregnant C57BL/6mice were randomly divided into three groups: a control group, a group receiving 0.2 μg/mL (LBPA), and a group receiving 2 μg/mL of BPA (HBPA), all via drinking water from gestational day 6 to the end of lactation. After weaning, one male mouse was randomly selected from each group (n = 7/group); these three mice were fed a normal diet and drinking water for 1 month. Levels of serum testosterone (T) and tumor necrosis factor (TNF)-α were then measured in all mice. Sperm count and the proportion of sperm malformation were also determined. The levels of Toll-like receptor 4 (TLR4), nuclear factor (NF)-κB, and aryl hydrocarbon receptor (AhR) protein expression in the testis tissue were determined. Analysis showed that the proportion of sperm malformation increased in the LBPA and HBPA groups (p < 0.05). Sperm count significantly decreased only in the HBPA group (p < 0.05), while the levels of serum TNF-α increased in the LBPA and HBPA groups (p < 0.05). Levels of serum T decreased significantly in the HBPA group, compared with controls (p < 0.05). Levels of TLR4 and NF-κB protein expression in the testis were significantly higher in the LBPA and HBPA groups (p < 0.05 or p < 0.01), while AhR protein expression was higher and seminiferous tubules in the testis showed more damage in the HBPA group compared to controls (p < 0.05 and p < 0.01, respectively). Our results showed that perinatal exposure to low or high doses of BPA decreased the capacity for spermatogenesis in male offspring, which may be associated with an inflammatory response activated by the TLR4/ NF-κB and AhR signaling pathways in the testis.

Maternal LPS exposure during pregnancy impairs testicular development, steroidogenesis and spermatogenesis in male offspring.

Lipopolysaccharide (LPS) is associated with adverse developmental outcomes including embryonic resorption, fetal death, congenital teratogenesis and fetal growth retardation. Here, we explored the effects of maternal LPS exposure during pregnancy on testicular development, steroidogenesis and spermatogenesis in male offspring. The pregnant mice were intraperitoneally injected with LPS (50 µg/kg) daily from gestational day (GD) 13 to GD 17. At fetal period, a significant decrease in body weight and abnormal Leydig cell aggregations were observed in males whose mothers were exposed to LPS during pregnancy. At postnatal day (PND) 26, anogenital distance (AGD), a sensitive index of altered androgen action, was markedly reduced in male pups whose mothers were exposed to LPS daily from GD13 to GD 17. At PND35, the weight of testes, prostates and seminal vesicles, and serum testosterone (T) level were significantly decreased in LPS-treated male pups. At adulthood, the number of sperm was significantly decreased in male offspring whose mothers were exposed to LPS on GD 13–17. Maternal LPS exposure during gestation obviously diminished the percent of seminiferous tubules in stages I–VI, increased the percent of seminiferous tubules in stages IX–XII, and caused massive sloughing of germ cells in seminiferous tubules in mouse testes. Moreover, maternal LPS exposure significantly reduced serum T level in male mice whose mothers were exposed to LPS challenge during pregnancy. Taken together, these results suggest that maternal LPS exposure during pregnancy disrupts T production. The decreased T synthesis might be associated with LPS-induced impairments for spermatogenesis in male offspring.

Prenatal Ethanol Exposure Delays the Onset of Spermatogenesis in the Rat

During late prenatal and early postnatal life, the reproductive system in males undergoes an extensive series of physiological and morphological changes. Prenatal ethanol (EtOH) exposure has marked effects on the development of the reproductive system, with long-term effects on function in adulthood. The present study tested the hypothesis that prenatal EtOH exposure will delay the onset of spermatogenesis. Development of the seminiferous tubules and the onset of spermatogenesis were examined utilizing a rat model of fetal alcohol spectrum disorder (FASD). Male offspring from ad libitum-fed control (C), pair-fed (PF), and EtOH-fed (prenatal alcohol exposure [PAE]) dams were terminated on postnatal (PN) days 5, 15, 18, 20, 25, 35, 45, and 55, to investigate morphological changes through morphometric analysis of the testes from early neonatal life through young adulthood. PAE males had lower relative (adjusted for body weight) testis weights compared with PF and/or C males from PN15 through puberty (PN45). In addition, fewer gonocytes (primordial germ cells) were located on the basal lamina on PN5, while more of those touching the basal lamina were dividing in PAE compared with PF and C males, suggesting delayed cell division and migration processes. As well, the percentage of tubules with open lumena was lower in PAE compared with PF and C males on PN18 and 20, and PAE males had fewer primary spermatocytes per tubule on PN18 and round spermatids per tubule on PN25 compared with C males. Finally, the percentage of tubules at stages VII and VIII, when mature spermatids move to the apex of the epithelium and are released, was lower in PAE compared with PF and/or C males in young adulthood (PN55). Maternal EtOH consumption appears to delay both reproductive development and the onset of spermatogenesis in male offspring, with effects persisting at least until young adulthood.

Maternal cypermethrin exposure during lactation impairs testicular development and spermatogenesis in male mouse offspring

Within the last decade, numerous epidemiological studies have demonstrated that endocrine disruptors are a possible cause for a decline in semen quality. Cypermethrin is a widely used pyrethroid insecticide, but little is known about its potentially adverse effects on male reproduction. In the present study, we investigated the effects of maternal cypermethrin exposure during lactation on testicular development and spermatogenesis in male offspring. Maternal mice were administered with cypermethrin (25 mg/kg) by gavage daily from postnatal day 0 (PND0) to PND21. Results showed that the weight of testes at PND21 was significantly decreased in pups whose mothers were exposed to cypermethrin during lactation. Maternal cypermethrin exposure during lactation markedly decreased the layers of spermatogenic cells, increased the inside diameter of seminiferous tubules, and disturbed the array of spermatogenic cells in testes of pups at PND21. In addition, maternal cypermethrin exposure during lactation markedly reduced mRNA and protein levels of testicular P450scc, a testosterone (T) synthetic enzyme. Correspondingly, the level of serum and testicular T at weaning was significantly decreased in pups whose mothers were exposed to cypermethrin during lactation. Although the expression of testicular T synthetic enzymes and serum and testicular T in adulthood had restored to control level, the decreased testicular weight and histological changes were irreversible. Importantly, the number of spermatozoa was significantly decreased in adult male offspring whose mothers were exposed to cypermethrin during lactation. In conclusion, maternal cypermethrin exposure during lactation permanently impairs testicular development and spermatogenesis in male offspring, whereas cypermethrin-induced endocrine disruption is reversible.

Maternal fenvalerate exposure during pregnancy persistently impairs testicular development and spermatogenesis in male offspring

Fenvalerate, a widely used pyrethroid insecticide, has been associated with poor semen quality. As yet, little is known about the effects of prenatal fenvalerate exposure on testicular development. The present study investigated the effects of prenatal fenvalerate exposure on testicular development and spermatogenesis. The pregnant mice were administered fenvalerate (30 mg/kg) by gavage daily from gestational day (gd) 13 to gd 18. The weights of testes and epididymides were significantly decreased in mice whose mothers were exposed to fenvalerate during pregnancy. Importantly, maternal fenvalerate exposure during pregnancy markedly decreased the number of mature seminiferous tubules (stages VII and VIII) in testes of adult male offspring. In addition, maternal fenvalerate exposure during pregnancy significantly reduced the number of epididymal spermatozoa in adult male offspring. Additional experiments showed that the level of serum testosterone (T) was significantly decreased in male fetuses whose mothers were exposed to fenvalerate during pregnancy. Correspondingly, mRNA and protein levels of P450 17α, a T synthetic enzyme, were significantly decreased in fetal testes. Moreover, the disruptive effect of prenatal fenvalerate exposure on testicular T synthesis was irreversible. In conclusion, prenatal fenvalerate exposure irreversibly impairs testicular development and spermatogenesis at least into early adulthood.

Lactational fenvalerate exposure permanently impairs testicular development and spermatogenesis in mice

Fenvalerate, a widely used synthetic pyrethroid insecticide, has been associated with poor semen quality in human being. However, little is known about the effects of lactational fenvalerate exposure on testicular development and spermatogenesis. The purpose of the present study was to investigate the effects of maternal fenvalerate exposure during lactation on testicular development and spermatogenesis in male offspring. Maternal mice were administered with fenvalerate (60 mg/kg) by gavage daily from postnatal day (PND) 0 to PND21. Lactational fenvalerate exposure markedly decreased the absolute and relative weights of testes and increased the number of apoptotic cells in testes of pups at weaning. Histological examinations showed abnormal seminiferous tubules with large vacuoles or complete spermatogenic failure in testes of fenvalerate-treated mice at weaning. Additional experiment showed that lactational fenvalerate exposure markedly reduced mRNA and protein levels of testicular P450scc, a testosterone (T) synthesis enzyme. Consistent with down-regulation of testicular P450scc, the level of serum and testicular T at weaning was significantly decreased in pups whose mothers were exposed to fenvalerate during lactation. Although the expression of testicular P450scc and serum and testicular T in adulthood restored to control level, the decreased weight of testes and histological changes were irreversible. Importantly, the percentage of mature seminiferous tubules (stages VII and VIII) and the number of spermatozoa were obviously decreased in adult male mice whose mothers were exposed to fenvalerate during lactation. Taken together, these results suggest that lactational fenvalerate exposure permanently impairs testicular development and spermatogenesis.

Lack of significant alteration in the prostate or testis of F344 rat offspring after transplacental and lactational exposure to bisphenol A.

Bisphenol A (BPA), a compound of great concern as an estrogenic xenobiotic, was assessed for its ability to cause alteration in the accessory sex organs and spermatogenesis in male offspring exposed preneonatally and neonatally. In a series of experiments focusing on rat sensitivity to gestational and lactational exposure to BPA, we investigated its effects on gestation period and reproductive organs in male offspring. In the first instance, BPA was administered to F344 female rats by gavage at 0, 7.5, 120 mg/kg/day during pregnancy and lactation period. There were no observable adverse effects in pregnant rats and the treatment did not induce any morphological abnormalities in the accessory sex organs of male offspring. However, lowered numbers of sperm in the testis were found with a dose of 120 mg/kg/day. In the second study, the same protocol with a higher number of male offspring was applied, but no reduction in the sperm count was apparent. We conclude that transplacental and lactational exposure to BPA dose not exert any adverse effects on morphogenesis of rat accessory sex organs or spermatogenesis.

Maternal cannabinoid exposure. Effects on spermatogenesis in male offspring.

Maternal exposure to cannabinoids influenced spermatogenesis and fertility in their male offspring examined at 60-80 days of age. Approximately 20% less spermatozoa were found in males whose mothers had received either the non-psychoactive cannabinol (CBN) or cannabidiol (CBD) on day 1 postpartum. Males exposed to the major psychoactive component of marihuana, delta 9-tetrahydrocannabinol (THC) appeared to have spermatozoa in number comparable to controls. This finding may be consistent with the additional observation that CBN or CBD, but not THC, reduced the percentage of successful impregnations by cannabinoid-exposed males. However, males exposed to each of these cannabinoids produced significantly less live offspring compared to controls. Plasma levels of testosterone and luteinizing hormone (LH) were reduced significantly in mice exposed to THC on day 12 of gestation, while testicular weight was reduced in adult mice exposed either on day 12 of gestation to CBD or on day 1 post-partum to THC. These results indicate that perinatal exposure to psychoactive and non-psychoactive components of marihuana can produce long-term disruption of testicular function including the spermatogenic as well as the steroidogenic components.