Effects of maternal 4-tert-octylphenol exposure on the reproductive tract of male rats at adulthood

Ameliorative Effects of Zinc Oxide, in Either Conventional or Nanoformulation, Against Bisphenol A Toxicity on Reproductive Performance, Oxidative Status, Gene Expression and Histopathology in Adult Male Rats

Bisphenol A (BPA) is a widely used endocrine disruptor that represents a significant risk to male reproductive function. Zinc (Zn) is vital for appropriate development of testes and to guarantee optimal testicular function and spermatogenesis. Our goal was to investigate if zinc oxide (ZnO), either in conventional or nanoformulation, could safeguard adult male rats' reproductive performance against the damaging effects of BPA. Signaling expression of CYP11A1 and Nrf-2 in the testis, testicular oxidant-antioxidant status, Bax/Bcl-2 apoptotic ratio, and histological examination of various reproductive organs were all evaluated. Twenty-eight adult male albino rats were divided randomly into 4 groups (7 animals each) including the control, BPA, conventional zinc oxide (cZnO) + BPA, and zinc oxide nanoparticles (ZnO-NPs) + BPA groups. The study was extended for 2 successive months. Our findings revealed strong negative effects of BPA on sperm cell characteristics such as sperm motility, viability, concentration and abnormalities. Additionally, BPA reduced serum levels of testosterone, triiodothyronine (T3), and thyroxine (T4). Also, it evoked marked oxidative stress in the testes; elevating malondialdehyde (MDA) and reducing total antioxidant capacity (TAC). BPA significantly downregulated testicular mRNA relative expression levels of CYP11A1 and Nrf-2, compared to control. Testicular apoptosis was also prompted by increasing Bax/ Bcl-2 ratio in testicular tissue. Histopathological findings in the testes, epididymis, prostate gland, and seminal vesicle confirmed the detrimental effects of BPA. Interestingly, cZnO and ZnO-NPs significantly alleviated all negative effects of BPA, but ZnO-NPs performed better. In conclusion, our findings point to ZnO, specifically ZnO-NPs, as a viable treatment for BPA-induced testicular dysfunction.

Impact of endocrine-active compounds on adrenal androgen production in pigs during neonatal period

This study investigated the impact of neonatal exposure to endocrine-active compounds (EACs): flutamide (antiandrogen), 4-tert-octylphenol (an estrogenic compound), and methoxychlor (an organochlorine insecticide exhibiting estrogenic, antiestrogenic and antiandrogenic activities) on androgen production within porcine adrenal glands. The expression of genes related to androgen synthesis and the level of androgen production were analyzed (i) in the adrenal glands of piglets exposed to EACs during the first 10 days of life (in vivo study), and (ii) in adrenal explants from sow-fed or formula-fed 10-day-old piglets incubated with EACs (ex vivo study). EACs affected the expression of genes linked to adrenal androgen biosynthesis. The prominent effect of methoxychlor on downregulation of StAR, CYP11A1 and HSD3B and upregulation of CYP17A1 and SULT2A1 were demonstrated. Furthermore, our study revealed divergent response to EACs between sow-fed and formula-fed piglets, suggesting that natural feeding may provide protection against adverse EACs effects, particularly those interfering with estrogens action.

Sex differences in 4-tert-octylphenol toxicokinetics: Exploration of sex as an effective covariate through an in vivo modeling approach

4-tert-octylphenol (4-tert-OP) is a potentially harmful substance, which is found widely in the environment. Nevertheless, information on the in vivo toxicokinetics of 4-tert-OP is lacking, and quantitative risk assessment studies are urgently needed. Therefore, we aimed to quantitatively identify differences in the toxicokinetics of 4-tert-OP and its distribution among tissues between sexes. To this end, following exposure of male and female rats to 10 or 50 mg/kg 4-tert-OP orally and 4 or 8 mg/kg 4-tert-OP intravenously, we conducted a quantitative analysis of samples using ultra-high performance liquid chromatography-tandem mass spectrometry. The results revealed that the 4-tert-OP plasma concentration profiles differed between sexes; however, systemic absorption of 4-tert-OP through the gastrointestinal tract occurred within 0.5 h of exposure in both sexes. Although small, the excretion percentage of 4-tert-OP in urine and feces was lower in males than females (0.06-0.08% vs. 0.82-1.11% of exposure). Significant sex differences were also confirmed in the tissue distribution patterns of 4-tert-OP, and overall, the average tissue distribution in males was lower than that in females. The distribution of 4-tert-OP to liver, adipose, spleen, kidney, brain, and lung in both sexes was predominant. A covariate exploration modeling approach revealed that sex explained the differences in 4-tert-OP toxicokinetics between sexes. These significant differences in the toxicokinetics and tissue distribution of 4-tert-OP between sexes will be important for the scientific precision human risk assessment of 4-tert-OP.

The protective effects of date seeds, in either conventional or nanoformulation, against bisphenol A-induced testicular toxicity: involvement of testicular expression of CYP11A1, Nrf-2 and Bax/Bcl-2 ratio

Background

Bisphenol A (BPA), an endocrine-disrupting chemical (EDC), is ubiquitous in our environment and poses a significant threat to male fertility. Date seeds (DSs) are used in folk medicine due to their antioxidant activity.

Aim

The purpose of this study was to assess the beneficial effects of DSs, whether in powder or nanoparticle form, against BPA-induced testicular oxidative challenges and apoptosis, aided by inspection of specific genes linked to fertility, oxidative stress and intrinsic mitochondrial pathway of apoptosis.

Methods

Thirty-five adult male albino rats were equally divided into 5 groups including control, BPA, BPA + date seeds powder "DSP", BPA + date seed nanoparticle 1/10 (DSNP 1/10) and BPA + DSNP 1/20 groups.

Results

TEM showed that the ball-mill method was effective to form DSNP with an average size of 20 nm. BPA significantly impaired sperm motility, morphology, viability and concentration. It also reduced serum testosterone levels and evoked marked oxidative stress in the testes. Additionally, serum levels of triiodothyronine and thyroxine were extremely reduced. Moreover, testicular mRNA relative expression levels of CYP11A1 and Nrf-2 were markedly downregulated. Testicular apoptosis was also promoted whereas Bax/Bcl-2 ratio was profoundly elevated. Histological pictures of the testes, epididymis, seminal vesicles and prostate confirmed the unfavorable effects of BPA. Surprisingly, we first demonstrated that DSs, specifically the nanoparticle form, strongly alleviated all of BPA's negative effects, with DSNP 1/20 achieving the best results.

Conclusion

Therefore, DSNP in both doses could be regarded as an ideal candidate for abating the male reproductive challenges caused by BPA.

Identification of endocrine-disrupting chemicals targeting the genes and pathways of genital anomalies in males

Hypospadias and cryptorchidism are the most common congenital malformations in male neonates, both of which are also the important clinical manifestations of testicular dysgenesis syndrome and share a same origin. Many studies have suggested that prenatal exposure to endocrine-disrupting chemicals (EDCs) is associated with hypospadias and cryptorchidism development. However, the consistent mechanisms remain unclear. To identify the key EDCs, genes and biological networks related to the development of hypospadias and cryptorchidism respectively and commonly, we conduct the present study and found a new method for predicting the correlation between the interactive genes of hypospadias/cryptorchidism and chemicals. Transcriptome profiles were obtained from the Comparative Toxicogenomics Database (CTD). Gene ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways enrichment analyses and protein-protein interaction (PPI) network were applied for integrative analyses. The rat model and molecular docking were applied to furtherly verifying the findings of the integrative analyses. Besides the highly related genes, most enriched pathways and chemicals for hypospadias and cryptorchidism respectively, we found hypospadias and cryptorchidism share many same highly associated EDCs (e.g., dibutyl phthalate) and genes (e.g., androgen receptor and estrogen receptor 1) through comparing highly related chemicals or genes of hypospadias and cryptorchidism respectively. GO and KEGG analysis showed that these same interactive genes were mainly enriched in steroidogenesis, response to steroid hormone and nuclear receptor activity. PPI network analysis identified 15 biological hub genes. Furtherly, hypospadias and cryptorchidism were induced by prenatal dibutyl phthalate exposure. Decreased serum testosterone level, downregulation of nuclear androgen-dependent and upregulation of cytoplasmic estrogen-dependent pathways may lead to hypospadias and cryptorchidism. This study proposed a new method for predicting the correlation between the interactive genes of hypospadias/cryptorchidism and chemicals and found that hypospadias and cryptorchidism share many same highly associated EDCs and genes.

Effects of Sex Steroid Receptor Agonists and Antagonists on the Expression of the FOXL2 Transcription Factor and its Target Genes AMH and CYP19A1 in the Neonatal Porcine Ovary

Recently, we have demonstrated that neonatal exposure to androgen and estrogen agonists or antagonists influenced the number of ovarian follicles in piglets. Since the FOXL2 transcription factor is required for proper ovarian follicle formation and activation, the objective of the study was to examine effects of exposure of the neonatal porcine ovary to testosterone propionate (TP; an androgen), flutamide (FLU; an antiandrogen), 4-tert-octylphenol (OP; compound with estrogenic activity), ICI 182,780 (ICI; an antiestrogen), and methoxychlor (MXC; compound with estrogenic, antiestrogenic and antiandrogenic properties) on FOXL2 expression and expression of its target genes, AMH and CYP19A1. Piglets were injected subcutaneously with TP, FLU, OP, ICI, MXC, or corn oil (control) between postnatal days 1 and 10 (n = 4/each group). Ovaries were excised from the 11-day-old piglets and the expression of FOXL2, AMH and CYP19A1 was examined using immunohistochemistry and/or real-time PCR and Western blot. FOXL2 was localized in stroma cells surrounding egg nests and in granulosa cells. TP, OP and MXC increased both FOXL2 and AMH mRNAs, while FLU and ICI decreased CYP19A1 mRNA. The increased FOXL2 protein abundance was found in all examined groups. In addition, TP, OP, ICI and MXC increased AMH protein abundance, while TP, FLU and OP decreased CYP19A1 protein abundance. In conclusion, neonatal exposure to sex steroid receptor agonists and antagonists increased FOXL2 expression at mRNA and/or protein levels and affected FOXL2 target genes in the ovaries of 11-day-old piglets. Therefore, it seems that impaired ovarian folliculogenesis induced by altered steroid milieu during the neonatal development period in pigs may, at least in part, involve FOXL2.

Advances in BPA-induced Oxidative Stress and Related Effects and Mechanisms in Liver, 1991-2017

Bisphenol A (BPA) is a widely spreading environmental endocrine disruptor . Its characteristics, including small doses and frequent contact, make it easy to enter human body through drinking water, food, air and other pathways, leading to tumors, infertility, and liver damage. The present review summarizes the underlying mechanism of oxidative stress and its related effects induced by BPA in the liver. The progress of the mechanism for oxidative stress induced by BPA is summarized, including mitochondrial dysfunction, lipid peroxidation and inflammation reaction, liver dyslipidemia, apoptosis, and cell death mechanism. In the future, it is necessary to elucidate the molecular mechanisms and timing of oxidative stress to clarify the effects on different exposures to different genders and growth stages. Besides, studying the toxic effects on BPA surrogates, BPA metabolites and BPA combined with other pollutants in the environment is beneficial to clarify the environmental and human health effects of BPA and provide technical reference for the development of practical control measures.

Effect of neonatal exposure to endocrine-active compounds on epigenetic regulation of gene expression in corpus luteum of gilts

Recently, we have demonstrated that neonatal exposure to environmental endocrine-active compounds (EACs) with androgenic/antiandrogenic and estrogenic/antiestrogenic activities led to morphological and functional changes in the porcine corpus luteum (CL). To gain insight into the regulatory mechanisms of the long-term effects of EACs, we analyzed the impact of neonatal exposure of such compounds on global DNA methylation and the expression of miRNA biogenesis components in the porcine CL. Piglets were injected subcutaneously with testosterone propionate (TP, an androgen), flutamide (FLU, an antiandrogen), 4-tert-octylphenol (OP, an estrogenic compound), ICI 182,780 (ICI, an antiestrogen), methoxychlor (MXC, a compound with mixed activities) or corn oil (control) between postnatal days 1 and 10 (n = 5/group). The CLs from sexually mature gilts were examined for global DNA methylation and for the abundance of proteins related to DNA methylation (DNMT1, DNMT3A and DNMT3B) and miRNA biogenesis (DROSHA, XPO5, DICER1, AGO2) using an enzyme-linked immunosorbent assay, Western blotting and immunohistochemical staining. ICI and MXC increased the global DNA methylation levels and DNMT1 protein abundance in the luteal tissue. OP treatment led to a lower DROSHA protein abundance, while ICI treatment resulted in a greater DROSHA protein abundance. Both FLU and ICI increased DICER1 protein abundance in the luteal tissue. In addition, XPO5 showed immunolocalization exclusively in small luteal cells in the OP-treated pigs, in contrast to localization in both small and large luteal cells in the controls. In conclusion, the changes in DNA methylation, as well as the altered miRNA biogenesis components, seem to be a part of the regulatory network that mediates the long-term effects of EACs on CL function in pigs.

Transcriptomic profiles of the ovaries from piglets neonatally exposed to 4-tert-octylphenol

The environmental pollutants with hormonal activities may influence steroid-mediated processes in neonatal ovaries and increase the incidence of reproductive disorders. The aim of the current study was to examine effects of 4-tert-octylphenol (OP), a non-ionic surfactant widely used in a variety of industrial applications which has been reported to mimic the 17β-estradiol activity, on the expression of protein-coding (mRNAs) and long non-coding (lncRNAs) transcripts in neonatal ovaries of the pig. By employing RNA-Seq we aimed to gain insights into regulatory networks underlying the OP effects on the follicular development in pigs. Piglets were injected (sc) daily with OP (100 mg/kg bw) or corn oil (controls) between postnatal Days 1 and 10 (n = 3/group). Ovaries were excised from the 11-day-old piglets and total cellular RNA was isolated and sequenced. Two hundred three differentially expressed genes (DEGs; P-adjusted < 0.05 and log₂ fold change ≥1.0) and 23 differentially expressed lncRNAs (DELs; P-adjusted < 0.05 and log₂ fold change ≥ 1.0) were identified in OP-treated piglet ovaries. The DEGs were assigned to Gene Ontology terms, covering biological processes, molecular functions and cellular components, which linked the DEGs to functions associated with movement of cell or subcellular component, regulation of plasma membrane bounded cell projection assembly as well as hydrolase and endopeptidase activity. In addition, STRING analysis demonstrated the strongest interactions between genes related to negative regulation of endopeptidase activity. Some correlations between DEGs and DELs were also found, revealing that the OP action on the ovary may be partially executed via the changes in the lncRNA expression. These results suggest that neonatal exposure of pigs to OP induces changes in the ovarian transcriptomic profile associated with genes encoding serine protease inhibitors and involved in steroid synthesis as well as genes linked to intracellular and membrane transport. We suggest that the changes in the mRNA and lncRNA expression in the ovaries of OP-treated piglets may disturb ovarian cellular function, including steroidogenesis, proliferation and apoptosis.

Effects of endocrine disrupting chemicals in pigs

Endocrine-disrupting chemicals (EDCs) are compounds that interfere with the expression, synthesis, and activity of hormones in organisms. They are released into the environment from flame retardants and products containing plasticizers. Persistent pesticides, such as dichlorodiphenyltrichloroethane (DDT) and hexachlorobenzene, also disrupt the endocrine system through interaction with hormone receptors. Endogenous hormones, such as 17β-estradiol (E2), are released in the urine and feces of farm animals and seep into terrestrial and aquatic ecosystems through sewage. Pigs are widely used as animal models to determine the effects of EDCs because they are physiologically, biochemically, and histologically similar to humans. EDCs primarily disrupt the reproductive and nervous systems of pigs. Moreover, embryonic development during the prenatal and early postnatal periods is particularly sensitive to EDCs. Mycotoxins, such as zearalenone, are food contaminants that alter hormonal activities in pigs. Mycotoxins also alter the innate immune system in pigs, making them vulnerable to diseases. It has been reported that farm animals are exposed to various types of EDCs, which accumulate in tissues, such as those of gonads, livers, and intestines. There is a lack of an integrated understanding of the impact of EDCs on porcine reproduction and development. Thus, this article aims to provide a comprehensive review of literature regarding the effects of EDCs in pigs.

4-Nonylphenol and 4-tert-octylphenol induce anxiety-related behaviors through alternation of 5-HT receptors and transporters in the prefrontal cortex

Environmental endocrine disruptors 4-nonylphenol (NP) and 4-tert-octylphenol (OP) may cast huge harm to human health. We used a rat model to observe the influence of NP or/and OP exposure on anxiety-related behaviors and the underlying mechanisms. Eighty male Sprague-Dawley (SD) rats were randomly divided into 10 groups: control group (corn oil), NP groups [30, 90, 270 mg/kg], OP groups [40, 120, 360 mg/kg] and NO groups [(mixed with the corresponding NP, OP alone exposed low, medium and high dose according to the natural environment exists NP:OP = 4:1]. The rats were orally administered every other day for 30 days. The neurobehaviors of rats were evaluated by open-field test (OFT) and elevated plus-maze test (EPM), and the concentrations of 5-HT, monoamine oxidase (MAOA), serotonin transporter (SERT), vesicular monoamine transporter 2 (VAMT2), 5-hydroxytryptamine 1A (5-HT_1A), 5-hydroxytryptamine 2A (5-HT_2A)，and 5-hydroxytryptamine 2C (5-HT_2C) in the rat prefrontal cortex were analyzed by ELISA. OFT and EPM tests showed that NP or/and OP exposure induced anxiety-related behaviors in rats. 5-HT levels were significantly increased compared with the control group. The levels of MAOA, SERT, VAMT2, 5-HT_1A, 5-HT_2A, and 5-HT_2C in the prefrontal cortex reduced in different degrees by high-doses NP or/and OP exposure. In summary, NP or/and OP exposure might cause anxiety-related behaviors in rats through regulating neurotransmitter 5-HT levels by altering the expression of 5-HT decomposition enzyme MAOA, transporters SERT and VMAT2, and 5-HT receptors 5-HT_1A, 5-HT_2A, and 5-HT_2C.

Neonatal Exposure to Agonists and Antagonists of Sex Steroid Receptors Affects AMH and FSH Plasma Level and Their Receptors Expression in the Adult Pig Ovary

Simple Summary

The ovarian development and the establishment of ovarian reserve during fetal and/or neonatal life is critical for future reproductive success. Many environmental chemicals are known to negatively affect development and physiology of human and animal ovaries by interfering with endocrine systems, resulting in aberrant reproductive functions. The present study shows the long-term impact of neonatal exposure to agonists and antagonists of sex steroid receptors on AMH and FSH signalling in the ovary of adult pigs. Our findings suggest alteration in ovarian follicle recruitment from ovarian reserve arising from neonatal disruption of androgen/estrogen signalling induced by environmental endocrine active compounds. Everyday use of many endocrine disruptors is already prohibited after their harmful impacts on normal physiology have become known. Nevertheless, market introduction of new chemicals with potential deleterious influence on reproductive physiology has continued. Our outcomes confirm that a neonatal window plays an essential role in the physiological programming of ovarian function in adult pigs. The influence of environmental chemicals on this critical neonatal window needs to be investigated in order to gain a comprehensive view of deleterious interactions between endocrine disrupting chemicals and ovarian function.

Abstract

In this study piglets were injected with testosterone propionate (TP, an androgen), flutamide (FLU, an antiandrogen), 4-tert-octylphenol (OP, an estrogenic compound), ICI 182,780 (ICI, an antiestrogen) or corn oil (controls) between postnatal days 1 and 10 (N = 5/group). Then plasma anti-Müllerian hormone (AMH) and follicle stimulating hormone (FSH) concentration and the expression of their receptors were examined in the adult pig ovary. TP and FLU decreased plasma AMH and FSH concentration. In preantral follicles, TP resulted in upregulation of AMHR2 and FSHR expression, but decreased AMH protein abundance. FLU upregulated AMHR2 expression, while OP increased FSHR mRNA. In small antral follicles, OP upregulated ACVR1 and BMPR1A expression, while FLU increased BMPR1A mRNA. FLU and ICI resulted in upregulation of AMHR2 expression. TP and FLU upregulated AMH expression, while it was downregulated in response to OP or ICI. Moreover, OP and ICI resulted in downregulation of FSHR expression, while FLU decreased FSHR protein abundance. In conclusion, neonatal exposure to either agonist or antagonist of androgen receptor affected AMH and FSH signalling systems in preantral follicles. In small antral follicles these systems were influenced by compounds with estrogenic, antiestrogenic, and antiandrogenic activity. Consequently, these hormonal agents may cause an accelerated recruitment of primordial follicles and affect the cycling recruitment of small antral follicles in pigs.

Neonatal exposure to agonists and antagonists of sex steroid receptors induces changes in the expression of oocyte-derived growth factors and their receptors in ovarian follicles in gilts

The objective of the present study was to examine the effects of neonatal exposure to either agonists or antagonists of androgen and estrogen receptors on the expression of growth and differentiation factor 9 (GDF9) and bone morphogenetic protein 15 (BMP15) and their cognate receptors (TGFBR1, BMPR1B, and BMPR2) in ovarian follicles of adult pigs. Piglets were injected subcutaneously with testosterone propionate (TP, an androgen, at 20 mg/kg bw), flutamide (FLU, an antiandrogen, at 50 mg/kg bw), 4-tert-octylphenol (OP, an estrogenic compound, 100 mg/kg bw), ICI 182,780 (ICI, an antiestrogen, 400 μg/kg bw), or corn oil (control) between postnatal Days 1 and 10 (n = 5/group). Ovarian follicles were excised from adult pigs on Days 8-11 of the estrous cycle. The expression of GDF9, BMP15, TGFBR1, BMPR1B and BMPR2 were examined in the population of preantral and small antral ovarian follicles using real-time PCR, Western blot and immunohistochemistry. In preantral follicles, the upregulation of GDF9 mRNA and protein expression was found in pigs that were neonatally exposed to TP or FLU, while administration of TP or ICI resulted in upregulation of BMP15. TGFBR1 and BMPR2 mRNA and protein expression were upregulated in preantral follicles of adult pigs that were neonatally exposed to TP or FLU, while administration of TP or ICI resulted in upregulation of BMPR1B. In small antral follicles, the mRNA and protein for TGFBR1 and BMPR2 were upregulated, while BMPR1B was downregulated in response to neonatal OP treatment. In addition, treatment with FLU upregulated BMPR1B and BMPR2 mRNA and protein expression, while downregulated the expression of TGFBR1. Moreover, GDF9 and BMP15 were immunolocalized in oocytes and granulosa cells of preantral follicles obtained from both control and treated ovaries. TGFBR1, BMPR1B and BMPR2 receptors were observed in the oocytes and granulosa cells of preantral follicles as well as in granulosa and theca cells of small antral follicles. In conclusion, the present study demonstrated neonatal exposure to either agonists or antagonists of androgen and estrogen receptors affected GDF9 and BMP15 signalling in ovaries of adult pigs. It seems that neonatal androgen excess or deficiency may lead to the acceleration of initial follicle recruitment, while neonatal exposure to compounds with antiandrogenic and estrogenic activity may disturb small antral follicles fate. Therefore, it confirms that neonatal window is critical for programming of ovarian function in pigs.

Association of serum levels of 4-tertiary-octylphenol with cardiovascular risk factors and carotid intima-media thickness in adolescents and young adults

In the family of alkylphenolic compounds, 4-tertiary-Octylphenol (4-t-OP) is extensively used in many products. In animal and in vitro studies, 4-t-OP exposure has been linked to cardiovascular disease (CVD) risk factors; however, there are no previous human epidemiological studies. In this study, 886 subjects were recruited from a cohort of Taiwanese adolescents and young adults to study the relationship between serum levels of 4-t-OP, CVD risk factors, and common carotid artery intima-media thickness (CIMT). The geometric mean (SD) 4-t-OP concentration was 32.52 (1.71) ng/mL. We found that serum levels of 4-t-OP were negatively associated with markers of glucose homeostasis (insulin, homeostasis model assessment of insulin resistance (HOMA-IR) and homeostasis model assessment of β-cell function (HOMA-β)), z score of body mass index (BMI z score) and CIMT but were positively associated with lipid profiles (high density lipoprotein cholesterol (HDL-C), Apolipoprotein A1). A one-unit elevation in natural log-transformed 4-t-OP (ng/mL) was negatively correlated with CIMT (mm) (β = -0.029, SE = 0.003, P < 0.001) in multiple linear regression analyses. The relationship between 4-t-OP and CIMT remained the same in all subgroups or if bisphenol A (BPA) was considered a covariate. In this study, we observed that higher levels of 4-t-OP levels were negatively correlated with markers of glucose homeostasis, BMI z score, and CIMT; positively correlated with lipid profiles (HDL-C and apolipoprotein A) in this cohort. Future research on exposure to 4-t-OP and CVD risk factors is warranted.

Fertaric Acid Protects from Octylphenol-Related Hepatotoxicity in Rats: Biochemical, Molecular, and Histopathological Studies

The endocrine-disrupting chemical 4-tert-octylphenol (OP) can mimic estrogen and testosterone hormones and threaten health; fertaric acid (FA) is a hydroxycinnamic acid found in grapefruit. This study aimed to investigate whether FA has a protective effect on 4-tert-octylphenol-related hepatotoxicity. Thirty male albino rats were divided into 5 equal groups of 6 rats each as follows: control group-administrated orally with 1 ml saline 3 days/week for 4 weeks; corn oil group-administrated orally with 1 ml corn oil 3 days/week for 4 weeks; FA-treated group-administrated orally with FA (45 mg /kg body weight) dissolved in saline 3 days/week for 4 weeks; OP-treated group-administrated orally with OP (40 mg /kg body weight) dissolved in corn oil 3 days/week for 4 weeks; FA + OP-treated group-administrated orally with FA (45 mg /kg body weight) dissolved in saline 3 days/week for 4 weeks then administrated orally with OP (40 mg/kg body weight) dissolved in corn oil 3 days/week for another 4 weeks. The results obtained showed that OP-exposed rats had significant increase in serum aspartate aminotransferase, alanine aminotransferase, γ-glutamyl transferase, lactate dehydrogenase, bilirubin, serum and liver tumor necrosis factor-α, interleukin-1β and malondialdehyde, serum interleukin-6 and interleukin-10 and significant decrease in serum alkaline phosphatase, acid phosphatase, serum and liver superoxide dismutase, glutathione peroxidase, and catalase. OP caused an inhibitory action on the gene expression of liver proteins. Rats treated with FA before OP exposure had near-normal values. In addition, FA prevented the degradation of liver deoxyribonucleic acid (DNA), and DNA reformation occurred. In conclusion, FA protects from dangerous OP-related hepatic effects, and these results were supported by molecular and histological investigations.

The toxicological effects of bisphenol A and octylphenol on the reproductive system of prepubertal male rats

The aim of the present study was to assess and compare the individual adverse effects of bisphenol A (BPA) and octylphenol (OP) on the reproductive system of prepubertal male rats. Rats were exposed to BPA and OP at doses of 125 and 250 mg/kg/day, by gavage, for 90 days. At the end of the study, the testes, epididymis, prostate gland, and seminal vesicle were removed and examined histopathologically. Also, 3-β-hydroxysteroid dehydrogenase expressions were analyzed and serum testosterone and luteinizing hormone (LH) levels were measured. Sperm head count of caput epididymis was performed using a hemocytometer. Seminiferous and epididymal round tubules were evaluated for tubule diameter, lumen diameter, and height of tubule epithelium. There were significant increases in relative testes weights in BPA125, OP125, and OP250 groups compared with the control. Atrophic tubules, pyknotic tubules, combined tubules, congestion, vacuolization of Sertoli cell, cell debris in the lumen, tubules without sperm, and degeneration of tubules were noted in the tissue specimens obtained from the treatment groups compared with the control group. Sperm head counts were decreased in all treatment groups except for the low-dose BPA group. Testosterone (T) levels decreased in the BPA and high-dose OP treatment groups. LH levels increased in BPA treatment groups and the low-dose OP treatment group and decreased in the high-dose OP group. Epithelial height of high-dose BPA and OP treatment groups increased compared with the control group. Furthermore tubular height of low-dose BPA and high-dose OP groups increased with respect to control levels. In the OP250 treatment group, thyroxine hormone level was increased compared to other groups. Also, in the OP125 treatment group, triiodothyronine hormone level was increased compared with other groups.

The results of this study showed that BPA and OP affect the steroidogenic enzyme expression and T production in Leydig cells. In conclusion, BPA and OP have adverse effects on the male reproductive system of prepubertal rats.

Melatonin controlled apoptosis and protected the testes and sperm quality against bisphenol A-induced oxidative toxicity

Epidemiological reports have indicated a correlation between the increasing bisphenol A (BPA) levels in the environment and the incidence of male infertility. In this study, the protective effects of melatonin on BPA-induced oxidative stress and apoptosis were investigated in the rat testes and epididymal sperm. Melatonin (10 mg/kg body weight (bw)) was injected concurrently with BPA (50 mg/kg bw) for 3 and 6 weeks. The administration of BPA significantly increased oxidative stress in the testes and epididymal sperm. This was associated with a decrease in the serum testosterone level as well as sperm quality, chromatin condensation/de-condensation level, and the percentage of haploid germ cells in the semen. BPA administration caused a significant increase in apoptosis accompanied by a decrease in the expression of the antiapoptotic proteins Bcl-2 in the testes and epididymal sperm. The concurrent administration of melatonin decreased oxidative stress by modulating the levels of glutathione, superoxide dismutase, and catalase as well as the malondialdehyde and hydrogen peroxide concentrations in the testes and sperm. Melatonin sustained Bcl-2 expression and controlled apoptosis. Furthermore, melatonin maintained the testosterone levels, ameliorated histopathological changes, increased the percentages of seminal haploid germ cells, and protected sperm chromatin condensation process, indicating appropriate spermatogenesis with production of functional sperm. In conclusion, melatonin protected against BPA-induced apoptosis by controlling Bcl-2 expression and ameliorating oxidative stress in the testes and sperm. Thus, melatonin is a promising pharmacological agent for preventing the potential reproductive toxicity of BPA following occupational or environmental exposures.

Birth outcome measures and prenatal exposure to 4-tert-octylphenol

Exposure to 4-tert-octylphenol (tOP) has been linked with adverse health outcomes in animals and humans, while epidemiological studies about associations between prenatal exposure to tOP and fetal growth are extremely limited. We measured urinary tOP concentrations in 1100 pregnant women before their delivery, and examined whether tOP levels were associated with birth outcomes, including weight, length, head circumference and ponderal index at birth. tOP could be detected in all samples, and the median uncorrected and creatinine-corrected tOP concentrations were 0.90 μg/L (range from 0.25 to 20.05 μg/L) and 1.33 μg/g creatinine (range from 0.15 to 42.49 μg/g creatinine), respectively. Maternal urinary log-transformed tOP concentrations were significantly negatively associated with adjusted birth weight [β (g) = -126; 95% confidence interval (CI): -197, -55], birth length [β (cm) = -0.53; 95% CI:-0.93, -0.14], and head circumference [β (cm) = -0.30; 95% CI: -0.54, -0.07], respectively. Additionally, considering sex difference, these significant negative associations were also found among male neonates, while only higher maternal tOP concentrations were associated with a significant decrease in birth weight among female neonates. This study suggested significant negative associations between maternal urinary tOP concentrations and neonatal sizes at birth, and they differed by neonatal sex. Further epidemiological studies are required to more fully elaborate the associations between prenatal tOP exposure and birth outcomes.

Bisphenol A Induces Apoptosis in Liver Cells through Induction of ROS

Oxidative stress mechanisms are involved in hepatotoxicity. The liver is reported to be affected by bisphenol A (BPA) in animals studies and has been also reported to possess hepatic toxicity. This study aimed to examine association between liver health status and the effects of BPA on the antioxidant defense systems and liver biomarkers. BPA (0, 2, 10, and 50 mg/kg) body weight was mixed in corn oil and intraperitoneally administered every forty-eight hours for 30 days in dose-dependent manner. There was no significant difference between the body weight and weight of rat liver in BPA-treated groups and control groups. The study results show that the levels of malondialdehyde (MDA) and hydrogen peroxide (H2O2) increased after exposure to BPA. However, the antioxidant enzymes catalase (CAT), superoxide dismutase (SOD), and glutathione peroxidase (GSH-PX) were significantly (P<0.001, P<0.05, and P<0.001, resp.) decreased at 50 mg/kg dosage. Liver markers activities such as lactate dehydrogenase (LDH), glutamic-oxalacetic transaminase (GOT), and glutamic-pyruvic transaminase (GPT) were significantly increased, while γ-glutamyl transferase (γ-GT) activity was decreased. BPA exposure increased activity of liver biomarkers indicating liver hyperactivity. Analysis of the liver section provided essential evidence of liver apoptosis. Moreover, BPA may lead to induced toxic response of liver oxidative system.

Capacitation and acrosome reaction differences of bovine, mouse and porcine spermatozoa in responsiveness to estrogenic compounds

Background

Endocrine disruptors are exogenous substance, interfere with the endocrine system, and disrupt hormonal functions. However, the effect of endocrine disruptors in different species has not yet been elucidated. Therefore, we investigated the possible effects of 17ß-estradiol (E2), progesterone (P4), genistein (GEN) and 4-tert-octylphenol (OP), on capacitation and the acrosome reaction in bovine, mouse, and porcine spermatozoa. In this in vitro trial, spermatozoa were incubated with 0.001-100 μM of each chemical either 15 or 30 min and then assessed capacitation status using chlortetracycline staining.

Results

E2 significantly increased capacitation and the acrosome reaction after 30 min, while the acrosome reaction after 15 min incubation in mouse spermatozoa. Simultaneously, capacitation and the acrosome reaction were induced after 15 and 30 min incubation in porcine spermatozoa, respectively. Capacitation was increased in porcine spermatozoa after 15 min incubation at the lowest concentration, while the acrosome reaction was increased in mouse spermatozoa after 30 min (P <0.05). E2 significantly increased the acrosome reaction in porcine spermatozoa, but only at the highest concentration examined (P <0.05). P4 significantly increased the acrosome reaction in bovine and mouse spermatozoa treated for 15 min (P <0.05). The same treatment significantly increased capacitation in porcine spermatozoa (P <0.05). P4 significantly increased capacitation in mouse spermatozoa treated for 30 min (P <0.05). GEN significantly increased the acrosome reaction in porcine spermatozoa treated for 15 and 30 min and in mouse spermatozoa treated for 30 min (P <0.05). OP significantly increased the acrosome reaction in mouse spermatozoa after 15 min (P <0.05). Besides, when spermatozoa were incubated for 30 min, capacitation and the acrosome reaction were higher than 15 min incubation in E2 or GEN. Furthermore, the responsiveness of bovine, mouse and porcine spermatozoa to each chemical differed.

Conclusions

In conclusion, all chemicals studied effectively increased capacitation and the acrosome reaction in bovine, mouse, and porcine spermatozoa. Also we found that both E2 and P4 were more potent than environmental estrogens in altering sperm function. Porcine and mouse spermatozoa were more responsive than bovine spermatozoa.

Do photoperiod and endocrine disruptor 4-tert-octylphenol effect on spermatozoa of bank vole (Clethrionomys glareolus)?

Photoperiod is an environmental signal that controls physiology and behavior of all organisms. Bank voles, which are seasonal breeders, are stimulated to reproduce by the long photoperiod associated with spring and summer. To date, physiology of bank vole spermatozoa has not been explored, although they constitute an interesting model for examining the relationship between photoperiod and xenoestrogen on spermatozoa function. In an attempt to evaluate the acute effect of 4-tert-octylphenol (OP) an in vitro system was used. Spermatozoa isolated from the cauda epididymidies of long-day (LD; 18 h light: 6 h darkness) and short-day (SD; 6 h light: 18 h darkness) bank voles were treated with two OP concentrations (10(-4) M and 10(-8)M, respectively). OP-treated spermatozoa were used for the examination of motility parameters (computer-assisted semen analyzer CEROS), acrosome integrity (Commassie blue staining), cAMP production (immunoenzymatic assay) and cell viability (flow-cytometry analysis). The study revealed the photoperiod-dependent effect of short OP-treatment on motility parameters of vole spermatozoa. In LD spermatozoa, an increase of velocities: (curvilinear velocity [VCL], average path velocity [VAP] straight line velocity [VSL]) and head activity (amplitude of the lateral head displacement, [ALH]) was found. Interestingly, in SD spermatozoa opposite effect on VCL, VAP, VSL and ALH was observed, however only after treatment with 10(-4)M OP. The dose-dependent influence of OP upon acrosome integrity, as well as cAMP levels, in relation to the reproductive status of voles was observed. Moreover, OP exposure affected spermatozoa morphology rather than spermatozoa viability.

Photodegradation of 4-tert octylphenol in aqueous solution promoted by Fe(III)

4-Tert-octylphenol (4-t-OP), a kind of endocrine-disrupting compounds, is widely distributed in natural water surroundings but can hardly be biodegraded. The advanced oxidation processes (AOPs) have been proved to be an efficient method to degrade 4-t-OP. In this study, the photodegradation of 4-t-OP in aqueous solution promoted by Fe(III) and the photooxidation mechanism were investigated. The ferric perchlorate was added into the aqueous solution for the production of hydroxyl radical. The efficiency of mineralization was monitored by total organic carbon analyzer, and photooxidation products were determined by high-performance liquid chromatography and liquid chromatography-mass spectrometer. 4-t-OP (2.4 × 10(-5) M) in aqueous solution was completely degraded after 45 min in the presence of Fe(III) (1.2 × 10(-3) M) under UV irradiation (λ = 365 nm). The optimal pH was 3.5. Higher Fe(III) concentration or lower initial 4-t-OP concentration led to increased photodegradation efficiency of 4-t-OP. The reaction was almost completely inhibited in the presence of 2-propanol. About 70 % mineralization of the solution was obtained after 50 h. The photooxidation product was supposed to be 4-tert-octyl catechol. 4-t-OP in aqueous solution can be degraded in the presence of Fe(III) under the solar irradiation. The photoinduced degradation is due to the reaction with hydroxyl radicals. It shows that the 4-t-OP is mineralized by the inducement of Fe(III) aquacomplexes, which exposes to solar light. Therefore, the results would provide useful information for the potential application of the AOPs to remove 4-t-OP in water surroundings.

Alfa-lipoic acid protects testosterone secretion pathway and sperm quality against 4-tert-octylphenol induced reproductive toxicity

The protective effect of α-lipoic acid (LA) (50 mg/kg bw) against 4-tert-octylphenol (OP) (50 mg/kg bw) induced reproductive toxicity in male rats was studied. LA was injected 1h prior to OP administration three times a week. OP caused significant increase in oxidative stress in hypothalamus and epididymal sperm, disturbed hormonal levels in serum, decreased sperm quality, increased DNA fragmentation and loss of 35 and 95 kDa proteins in sperm, as well as elevated proliferating index in testis. LA protected against oxidative stress through promoting the levels of glutathione and glutathione-S-transferase in hypothalamus and sperm. In addition, LA prevented the decrease in testosterone, dehydroepiandrosterone sulfate, 3β-hydroxysteroid dehydrogenase, and inhibited the elevations in sex-hormone-binding globulin levels and showed normal sperm quality. LA modulated proliferation of germ cell, protected against DNA fragmentation and maintained membrane protein organization in the sperm. In conclusion, LA normalized oxidative stress and protected testosterone synthesis pathway across hypothalamus-testicular axis and sperm quality indicating its defensive influence against OP-induced oxidative reproductive dysfunction in male rats.

Photocatalytic degradation of 4-tert-octylphenol in a spiral photoreactor system

A spiral photoreactor system (SPS) was developed for the degradation of 4-tert-octylphenol (4-t-OP) in aqueous phase. 4-t-OP was previously considered as a endocrine disrupting compound frequently present in water. The direct photodegradation reaction caused by the SPS was found to accord with the characteristic of apparent first-order reaction with reaction rate constant k = 4.8 x 10(-2) min(-1). However, the direct photodegradation reaction could not make the 4-t-OP mineralized. The photodegradation efficiency increased from 88% to 91.2% in 45 min irradiation period after the internal surface of SPS was sintered with TiO2 thin film as catalyst. Catalyst concentration, number of catalyst coating layers and initial concentration of 4-t-OP were proven to be the factors affecting the photocatalytic degradation performance of the SPS on aqueous 4-t-OP. The degradation mechanism was investigated and the byproducts were analyzed using total organic carbon analyzer (TOC) and LC-MS. The possible chemical structures of the products were suggested. SPS with single layer of TiO2 prepared by sintering 13.6% of TiO2 precursor was proven to be more efficient than most of previous systems for removal of 4-t-OP from aqueous phase. 28.3% of the 4-t-OP was mineralized in 45 min according to the decreased amount of TOC value.

Xenoestrogenic chemicals effectively alter sperm functional behavior in mice

Xenoestrogenic compounds (XCs) can disrupt endogenous hormone function and affect sperm function by binding to receptors on sperm membrane. Albeit spermatozoa are potentially a useful model for screening estrogenic activities of endocrine disruptors, high-quality in vitro test system that examination of the XCs effects on sperm function is required. The objective of this study was to compare the effects of XCs (genistein and 4-tert-octylphenol) to those of steroids (estrogen and progesterone) and heparin on in vitro capacitation and acrosome reaction (AR) in mouse spermatozoa. Mouse spermatozoa were incubated with various concentrations (0.001-100 μM) of each chemical for 15 or 30 min, and then capacitation and AR were assessed using chlortetracycline. All chemicals studied effectively alter capacitation and/or AR in mouse spermatozoa with different manner. Therefore, we believed that our system will provide a good in vitro model system to characterize the physiological effect of XCs especially when compared with steroids.

Vitamin C coadministration augments bisphenol A, nonylphenol, and octylphenol induced oxidative damage on kidney of rats

The aim of this study was to investigate whether bisphenol A (BPA), nonylphenol (NP), and octylphenol (OP) induce oxidative stress on the kidney tissue of male rats and whether coadministration of vitamin C, an antioxidant, can prevent any possible oxidative stress. The Wistar male rats were divided into seven groups, including control, BPA, NP, OP, BPA+C, NP + C, OP +C. BPA, NP, and OP (25 mg/kg/day) was administered alone; vitamin C (60 mg/kg/day) was administered along with BPA, OP, and NP to the rats for 50 days. There was a decrease in serum concentration of blood urea nitrogen (BUN) in NP and OP groups compared with control group. Vitamin C coadministration with BPA, NP, and OP did not produce significant increase in BUN concentration in BPA +C, NP+ C, and OP + C group as compared with BPA, NP, and OP groups, respectively. The lowest serum creatinine activity and the highest lactate dehydrogenase (LDH) activity was present in kidney of BPA+C, NP+C and OP+C groups compared with BPA, NP, and OP groups. The malondialdehyde (MDA) levels were significantly higher while glutathione (GSH) levels were lower in treatment groups than controls. Furthermore, an increase was observed in MDA levels whereas a decrease was observed in GSH levels in BPA+ C, NP + C, and OP+ C groups compared with BPA, NP, and OP groups, respectively. These finding are in accordance with immunohistochemical staining of MDA and GSH. Histopathological examination of the kidneys of rats in BPA, OP, NP, BPA+ C, NP + C, and OP+ C groups revealed necrotic lesions, congestion, and mononuclear cell infiltration. In conclusion BPA, NP, and OP might induce oxidative damage in kidney of rats. In addition, coadministration of vitamin C with BPA, NP, and OP to male rats augments this damage in the kidney of male rats.

Embryonic exposure to octylphenol induces changes in testosterone levels and disrupts reproductive efficiency in rats at their adulthood

The purpose of the present study was to investigate the effects of prenatal exposure to octylphenol (OP) at the dose of 50mg/kg body weight on days 1, 7 and 14 of pregnancy on reproductive health of male rats at adulthood. F1 male rats from control and OP exposed animals were weaned and maintained up to postnatal day (PND) 100. The indices of testis, epididymis and seminal vesicles were significantly decreased in male rats exposed to OP during embryonic development when compared with controls. Significant reduction in the epididymal sperm count, viable sperms and motile sperms and number of tail coiled sperms (HOS-test) were observed in experimental rats when compared to control rats. The levels of serum testosterone and also activity levels of testicular hydroxysteroid dehydrogenases were significantly decreased with a significant increase in the serum follicle stimulating and leutinizing hormones in experimental rats. Furthermore, embryonic exposure to OP caused significant down regulation of StAR, 3ß hydroxysteroid dehydrogenase and 17ß hydroxysteroid dehydrogenase mRNAs in testis of adult rats as compared to control rats. The results of fertility studies revealed that there was an increase in the mating index in experimental rats with an increase in the pre- and post-implantation losses in rats cohabited with treated animals indicating poor male reproductive performance.

Pro-oxidant effect of vitamin C coadministration with bisphenol A, nonylphenol, and octylphenol on the reproductive tract of male rats

This study was performed to investigate whether bisphenol A (BPA), nonylphenol (NP), and octylphenol (OP) induce oxidative stress on the reproductive tract of male rats and if coadministration of vitamin C can prevent any possible oxidative stress. Wistar male rats were divided into seven groups as control (vehicle; olive oil), BPA, NP, OP, BPA+C, NP+C, and OP+C. BPA, OP, and NP groups (25 mg/kg/day) were administered orally to rats three times a week for 45 days. In BPA+C, NP+C, and OP+C groups, vitamin C (60 mg/kg/day) was administered orally along with BPA, OP, and NP (25 mg/kg/day) treatments. Malondialdehyde (MDA) appeared at significantly higher concentrations in BPA-, NP-, and OP-treated groups, when compared to control group. No significant decrease was observed in testes MDA levels of vitamin C coadministrated groups, compared with BPA, NP, and OP treatment groups. Decreased levels of reduced glutathione (GSH) were found in testes of BPA-, NP-, OP-treated rats. No significant increase was observed in testes GSH levels of BPA+C, NP+C, and OP+C groups, compared with BPA, NP, and OP treatment groups. Histological examination showed that vitamin C coadministrated groups had much more congestion areas, atrophy, and germinal cell debris in testes than those observed in other groups. Abnormal sperm percentages of BPA, BPA+C, NP+C, and OP+C groups were increased. In conclusion, the present results demonstrated that BPA, NP, and OP generate reactive oxygen species that cause oxidative damage in testes of rats. Coadministration of vitamin C aggravates this damage.

Morphological comparison of the testis and efferent ductules between wild-type and estrogen receptor alpha knockout mice during postnatal development

Estrogen and the estrogen receptor (ER)alpha play an important role in the male reproductive tract and in fertility. Previous studies demonstrated that disruption of ERalpha function resulted in abnormal morphology of the testis and efferent ductules (EDs) of adult mice. However, the effect of a lack of a functional ERalpha during early postnatal development has not been determined. The present study is an evaluation of morphological changes effected by a lack of ERalpha in the male reproductive tract during the postnatal period. Age-equivalent wild-type and ERalpha knockout (alphaERKO) mice at 10, 18, 35 and 60 days of age after birth were used for morphological comparison of the testes and ED. Light microscopic examination of the testes of the alphaERKO mouse revealed a dramatic dilation of the rete testis as early as 10 days of age, premature lumen formation, reduced epithelial height and greatly dilated lumen of seminiferous tubules as early as 18 days of age. The proximal ED of the alphaERKO mouse showed lumen dilation, reduction of epithelial height and a decrease of nuclear height as early as 10 days of age. Similar, but somewhat less severe, morphological abnormalities were observed in the distal ED of the alphaERKO mouse. These results indicate that a lack of functional ERalpha leads to morphological changes of the testis and ED of the early postnatal developing mouse. Based on these observations, we conclude that ERalpha plays an important role in normal development of the testis and ED, not only during adulthood but also during the entire postnatal period and presumably during fetal development.

Prepubertal octylphenol exposure up-regulate BRCA1 expression, down-regulate ERalpha expression and reduce rat mammary tumorigenesis

BACKGROUND

Endogenous estrogens play an important role in the development of breast cancer. Octylphenol (OP) and genistein (GEN) are estrogen-like chemicals. Prepubertal estradiol and genistein exposure can up-regulate BRCA1 mRNA in mammary gland and reduce futuer breast cancer risk. In the present study, the effects of prepubertal exposure to high-dose OP and GEN on mammary carcinogenesis and the association with the expression of BRCA1 and ERalpha were investigated.

METHODS

Prepubertal female Sprague-Dawley rats were exposed to 20, 40, 80mg/kg OP daily from postnatal day (PND) 22-28, subsequently, the rats were given a single dose of 100mg/kg 7,12-dimethylbenz [a] anthracene (DMBA) on PND42 to induce mammary tumor.

RESULTS

The incidence of DMBA-induced mammary tumors significantly decreased when rats were treated with 40mg/kg OP. BRCA1 mRNA and protein expression were found up-regulated and ERalpha expression was down-regulated in the mammary tumor when rats were exposed to 40mg/kg octylphenol.

CONCLUSION

Exposure 40mg/kg octylphenol can reduce later breast cancer risk in prepubertal Sprague-Dawley rats, the protective effect of OP is associated with persistent up-regulation of BRCA1 and down-regulation of ERalpha in the mammary tumor.

Effects of chronic exposure to octylphenol on the male rat reproductive system

p-tert-Octylphenol (OP) is a degradation product of alkylphenol ethoxylates. OP is an endocrine disruptor known to bind to the estrogen receptor; however, effects on males are controversial. The objective of this study was to evaluate the effects of chronic exposure to OP on male reproduction. Adult Sprague-Dawley rats were administered OP for 60 d, representing 1.5 cycles of spermatogenesis. Experimental groups included a vehicle control, and three doses of OP (25, 50, or 125 mg/kg body weight [bw]) administered daily by gavage. There was a significant decrease in body weight in the 125-mg/kg group after 60 d of treatment. Both testicular and epididymal weights and histology were not altered by treatment with OP at any of the doses administered. There were no marked differences in cauda epididymal sperm counts at any doses; however, total percent sperm motility was significantly lower in rats exposed to the intermediate dose (50 mg/kg bw). There was an increase in percent static sperm cells in all OP-treated groups, with the intermediate dose (50 mg/kg) displaying a significantly higher proportion of static cells relative to untreated controls. Caput epididymal sperm motility was unaltered by OP treatment. Gene expression profiles of testes from control and high-dose-exposed rats indicate that 14 genes were modulated by at least twofold, although these changes were not statistically significant. Taken together, results from this study indicate that OP treatment of adult rats does not appear to exert major effects on male reproductive endpoints at relevant environmental exposure doses.

Histopathological effects of 4-tert-octylphenol treatment through the pregnancy period, on the pituitary, adrenal, pancreas, thyroid and parathyroid glands of offspring rats at adulthood

The present study was carried out to investigate the effects of 4-tert-octylphenol (OP) exposure at fetal period on adrenal, pituitary, thyroid+parathyroid and pancreas tissues of male and female offsprings. Pregnant rats were treated with OP (100 or 250mg/(kgday)) in vehicle (corn oil) or vehicle alone daily from day 1 to 20 of pregnancy. After birth, young rats were allowed to growth until adulthood. While there were no differences in data of organ weight between control and treatment groups, in contrast, a decrease of relative organ weights of thyroid+parathyroid and adrenal in high dose treatment group in male rats, otherwise an increase of final body weights was found in 250mg/(kgday) treatment group in all rats. Also, a lot of histopathological findings were observed in investigated tissues. The results of this study suggest that, the octylphenol which was applied in fetal period causes negative effects on the adrenal, pituitary gland, thyroid+parathyroid and pancreas in rats.

The effect of vitamin C on bisphenol A, nonylphenol and octylphenol induced brain damages of male rats

Bisphenol A (BPA), nonylphenol (NP) and octylphenol (OP) are endocrine-disrupting chemicals that has been shown to exert both toxic and estrogenic effects on mammalian cells. The aim of this study was to investigate if BPA, NP and OP induce oxidative stress on the brain tissue of male rats and if co-administration of vitamin C, an antioxidant, can prevent any possible oxidative stress. The male rats were divided into seven groups as control (vehicle), BPA, NP, OP, BPA+C, NP+C, OP+C. BPA, OP and NP (25 mg/(kg day)) were administrated orally to male Wistar rats for 45 days. In vitamin C co-administration groups (BPA+C, NP+C, OP+C), vitamin C (60 mg/(kg day)) were administrated orally along with BPA, OP and NP (25 mg/(kg day)) treatments. The rats in the control group received olive oil orally. The final body and absolute organ weights of treated rats did not show any significant difference when compared with the control group. Also, there were no significant difference in relative organ weights of BPA, NP, OP, BPA+C and NP+C groups when compared with control group. Only, relative organ weights were increased significantly in OP+C group compared with control group. Decreased levels of reduced glutathione (GSH) were found in the brains of BPA, NP, OP treated rats. The end product of lipid peroxidation, malondialdehyde (MDA), appeared at significantly higher concentrations in the BPA, NP, and OP treated groups when compared to the control group. On the other hand, there were no changes in the brain MDA and GSH levels of BPA+C, NP+C and OP+C groups compared with BPA, NP and OP treatment groups, respectively. In histopathologic examination, the vitamin C co-administrated groups had much more hyperchromatic cells in the brain cortex than that observed in the groups treated with only BPA, NP, and OP. The results of this study demonstrate that BPA, NP and OP generate reactive oxygen species that caused oxidative damage in the brain of male rats. In addition, vitamin C co-administration along with BPA, NP, and OP aggravates this oxidative damage in the brain of rats.

The control of sexual differentiation of the reproductive system and brain

This review summarizes current knowledge of the genetic and hormonal control of sexual differentiation of the reproductive system, brain and brain function. While the chromosomal regulation of sexual differentiation has been understood for over 60 years, the genes involved and their actions on the reproductive system and brain are still under investigation. In 1990, the predicted testicular determining factor was shown to be theSRYgene. However, this discovery has not been followed up by elucidation of the actions of SRY, which may either stimulate a cascade of downstream genes, or inhibit a suppressor gene. The number of other genes known to be involved in sexual differentiation is increasing and the way in which they may interact is discussed. The hormonal control of sexual differentiation is well-established in rodents, in which prenatal androgens masculinize the reproductive tract and perinatal oestradiol (derived from testosterone) masculinizes the brain. In humans, genetic mutations have revealed that it is probably prenatal testosterone that masculinizes both the reproductive system and the brain. Sexual differentiation of brain structures and the way in which steroids induce this differentiation, is an active research area. The multiplicity of steroid actions, which may be specific to individual cell types, demonstrates how a single hormonal regulator, e.g. oestradiol, can exert different and even opposite actions at different sites. This complexity is enhanced by the involvement of neurotransmitters as mediators of steroid hormone actions. In view of current environmental concerns, a brief summary of the effects of endocrine disruptors on sexual differentiation is presented.