Effects of p,p'-dichlorodiphenyldichloroethylene on the expressions of transferrin and androgen-binding protein in rat Sertoli cells

1,1,1-trichloro-2,2-bis (p-chlorophenyl)-ethane (DDT) and 1,1-Dichloro-2,2-bis (p, p'-chlorophenyl) ethylene (DDE) as endocrine disruptors in human and wildlife: A possible implication of mitochondria

1,1,1-trichloro-2,2-bis (p-chlorophenyl)-ethane (DDT) and its main metabolite 1,1-Dichloro-2,2-bis (p, p'-chlorophenyl) ethylene (DDE) act as endocrine disruptors in humans and wildlife. Immunomodulatory functions have also been attributed to both xenobiotics. DDT was banned in the 1970s due to its toxicity, but it is still produced and used for indoor residual spraying with disease vector control purposes. Due to their persistence and lipophilic properties, DDT and DDE can bioaccumulate through the food chain, being stored in organisms' adipose depots. Their endocrine disruptor function is mediated by agonist or antagonist interaction with nuclear receptors. Present review aimed to provide an overview of how DDT and DDE exposure impacts reproductive and immune systems with estrogen-disrupting action in humans and wildlife. Studies showing DDT and DDE impact on mitochondrial function and apoptosis pathway will also be reviewed, suggesting the hypothesis of direct action on mitochondrial steroid receptors.

Possible Protective Effects of Curcumin via Modulating of Androgen Receptor (AR) and Oct2 Gene Alterations in Cisplatin-Induced Testicular Toxicity in Rat

BACKGROUND

Cisplatin is a chemotherapeutic drug used to treat testicular cancer that induces testicular toxicity. This study aimed to investigate the possible role of androgens, androgen receptor, and organic cation transporter 2 (OCT2) in the protective effects of curcumin on cisplatininduced testicular toxicity.

METHODS

Thirty male Wistar rats were divided into five groups: 1- control (normal saline, 0.5 ml ip, daily for 10 consecutive days); 2- cisplatin (10 mg/kg ip, single dose at the first day); 3- cisplatin + curcumin (10 mg/kg ip, dissolved in 5% DMSO, daily for 10 consecutive days); 4- cisplatin + vehicle (DMSO 5%, 0.3 ml ip); and 5- curcumin (10 mg/kg ip). At the end of the study, a blood sample was obtained for testosterone measurement. The left testis was kept at -80. to measure androgen receptor (AR) and type 2 organic cation transporter (OCT2) gene expression and the right testis were kept in 10% formalin for histological analysis.

RESULTS

Cisplatin significantly decreased serum testosterone, declined testis AR gene expression, and increased OCT2 gene expression in testis (p<0.01). Curcumin treatment significantly prevented these alterations in testosterone and gene expressions (p<0.01). Moreover, curcumin significantly reversed the cisplatin-induced kidney tissue injury and increased spermatid and spermatozoa.

CONCLUSION

It is concluded that the ameliorative effect of curcumin in cisplatin-induced reproductive disorders was due to the modulation of testosterone and androgen receptors.

Review of the Reproductive Toxicity of T-2 Toxin

T-2 toxin, an inevitable environmental pollutant, is the most toxic type A trichothecene mycotoxin. Reproductive disruption is a key adverse effect of T-2 toxin. Herein, this paper reviews the reproductive toxicity of T-2 toxin and its mechanisms in male and female members of different species. The reproductive toxicity of T-2 toxin is evidenced by decreased fertility, disrupted structures and functions of reproductive organs, and loss of gametogenesis in males and females. T-2 toxin disrupts the reproductive endocrine axis and inhibits reproductive hormone synthesis. Furthermore, exposure to T-2 toxin during pregnancy results in embryotoxicity and the abnormal development of offspring. We also summarize the research progress in counteracting the reproductive toxicity of T-2 toxin. This review provides information toward a comprehensive understanding of the reproductive toxicity mechanisms of T-2 toxin.

Downregulation of steroid hormone receptor expression and activation of cell signal transduction pathways induced by a chiral nonylphenol isomer in mouse sertoli TM4 cells

Nonylphenols (NPs) are considered as important environmental toxicants and potential endocrine disrupting compounds which can disrupt male reproductive system. 4-[1-Ethyl-1-methylhexy] phenol (4-NP₆₅ ) is one of the main isomers of technical nonylphenol mixtures. In the present study, effect of NPs was evaluated from an isomer-specific viewpoint using 4-NP₆₅ . Decreased mRNA expression levels of estrogen receptor (ER)-α, ER-β, androgen receptor (AR) and progesterone receptor (PR) were observed in the cells exposed to 4-NP₆₅ for 24 h. Furthermore, 4-NP₆₅ treatment evoked significant decrease in protein expression levels of ER-α and ER-β. Levels of mullerian inhibiting substance and transferrin were found to change significantly in 4-NP₆₅ challenged cells. Additionally, JNK1/2-MAPK pathway was activated due to 4-NP₆₅ exposure, but not ERK1/2 and p38-MAPK pathways. Meanwhile, 4-NP₆₅ increased the p-Akt level and showed no effects on the Akt level which indicated that Akt pathway was activated by 4-NP₆₅ . In conclusion, these findings have shown that 4-NP₆₅ exposure affected expression of cell receptors and cell signaling pathways in Sertoli TM4 cells. We proposed that molecular mechanism of reproductive damage in Sertoli cells induced by NPs may be mediated by cell receptors and/or cell signal transduction pathways, and that the effects were dependent on the side chain of NP isomers. © 2016 Wiley Periodicals, Inc. Environ Toxicol 32: 469-476, 2017.

Impact of low molecular weight phthalates in inducing reproductive malfunctions in male mice: Special emphasis on Sertoli cell functions

Phthalates are commonly used as plasticizers in a variety of products. Since they have been identified as endocrine-disrupting chemicals (EDCs), effect of phthalates on human health is a major concern. In this study, we evaluated individual as well as combined mixture effects of three low molecular weight phthalates on the reproductive system of male mice, specifically on the Sertoli cell structure and function. In order to analyze the blood testes barrier (BTB) dynamics, primary culture of Sertoli cells from 3-weeks old male mice was used for mimicking typical tight junction structures. Male mice were exposed to long-term (45 days) and combined mixture of three phthalates, diethyl phthalate (DEP), diphenyl phthalate (DPP), and dimethyl isophthalate (DMIP) between pre-pubertal to adult stage. Our data showed significant decrease (p < 0.05) in the rates of transcription of certain prominent Sertoli cell specific genes like transferrin, testin and occludin. Moreover, we also observed significant decreases in the expression of proteins like 3β-HSD, connexin-43 and occludin in testicular lysates of treated animals (p < 0.05). The transmission electron microscopic analysis revealed that the test compounds significantly altered the structural integrity of Sertoli cells. The significant changes of Sertoli cell tight junction structure by test compounds were associated with phosphorylation of ERK. Taken together, our study suggests that low molecular weight phthalates may affect male fertility by altering both structural and functional integrity of Sertoli cells in testes.

Effects of icariin on reproductive functions in male rats

The present study investigated the effects and potential mechanism(s) of action of icariin on the reproductive functions of male rats. Adult rats were treated orally with icariin at doses of 0 (control), 50, 100, or 200 mg/kg body weight for 35 consecutive days. The results show that icariin had virtually no effect on the body weight or organ coefficients of the testes or epididymides. However, 100 mg/kg icariin significantly increased epididymal sperm counts. In addition, 50 and 100 mg/kg icariin significantly increased testosterone levels. Real-time PCR suggests icariin may be involved in testosterone production via mRNA expression regulation of genes such as peripheral type benzodiazepine receptor (PBR) and steroidogenic acute regulatory protein (StAR). Furthermore, 100 mg/kg icariin treatment also affected follicle stimulating hormone receptor (FSHR) and claudin-11 mRNA expression in Sertoli cells. Superoxide dismutase (SOD) activity and malondialdehyde (MDA) levels were measured in the testes; 50 and 100 mg/kg icariin treatment improved antioxidative capacity, while 200 mg/kg icariin treatment upregulated oxidative stress. These results collectively suggest that icariin within a certain dose range is beneficial to male reproductive functions; meanwhile, higher doses of icariin may damage reproductive functions by increasing oxidative stress in the testes.

Effects of nonylphenol exposure on expression of cell receptors and secretory function in mouse Sertoli TM4 cells

The aim of this study was to investigate the effects of nonylphenol (NP) exposure on the expression of cell receptors and secretory function in mouse Sertoli TM4 cells. There were no significant changes in mRNA expression of estrogen receptor (ER)-α and toll like receptor (TLR)-4 in the cells exposed to NP for 24h. However, the mRNA expression levels of ER-β, progesterone receptor (PR) and androgen receptor (AR) were down-regulated in NP groups. Furthermore, NP treatment evoked significant changes in protein expression levels of ER-β and follicle-stimulating hormone receptor (FSHR). There were significant changes in the mRNA expression levels of vinculin, N-cadherin and occludin, but not vimentin. Levels of inhibin B, androgen binding protein (ABP) and transferrin (Trf) were found to change significantly in NP challenged cells. Additionally, the decrease of nitric oxide (NO) production and inducible nitric oxide synthase (iNOS) mRNA expression and increase of cytokine levels were simultaneously found in NP stimulated TM4 cells. In conclusion, these findings have shown that NP exposure affected expression of cell receptors and may damage specific secretory function of Sertoli TM4 cells, which may be associated with the male-specific reproductive toxicity of NP.

Occupational exposure to pesticides and consequences on male semen and fertility: a review

Exposure to pesticides affects many body organs including reproductive system. Disorder of the reproductive system leads to infertility and therefore has been in the center of attention within the recent decades. Pesticides are one of the compounds that might reduce the semen quality in the exposed workers according to current knowledge. Although many underlying mechanisms have been proposed, the mechanisms of action are not clarified yet. The object of the present review was to criticize all the results of studies which evaluated the pesticide effects on male reproductive system. Results indicate that semen changes are multifactorial in the workers exposed to pesticides as there are numerous factors affecting sperm quality in occupational exposures. Majority of pesticides including organophosphoruses affect the male reproductive system by mechanisms such as reduction of sperm density and motility, inhibition of spermatogenesis, reduction of testis weights, reduction of sperm counts, motility, viability and density, and inducing sperm DNA damage, and increasing abnormal sperm morphology. Reduced weight of testes, epididymis, seminal vesicle, and ventral prostate, seminiferous tubule degeneration, change in plasma levels of testosterone, follicle-stimulating hormone (FSH), and luteinizing hormone (LH), decreased level and activity of the antioxidant enzymes in testes, and inhibited testicular steroidogenesis are other possible mechanisms. Moreover, DDT and its metabolites have estrogenic effects on males. Although effect of pesticides on sperm quality is undeniable, well-designed long-term studies are needed to elucidate all the possible affecting variables such as socioeconomic, cultural, nutritional, occupational, physical, and clinical characteristics alongside pesticides.

p,p'-DDE induces apoptosis and mRNA expression of apoptosis-associated genes in testes of pubertal rats

One,1-dichloro-2,2 bis(p-chlorophenyl) ethylene (p,p'-DDE), the major metabolite of 2,2-bis(4-chlorophenyl)-1,1,1-trichloroethane (DDT), is a known persistent organic pollutant and male reproductive toxicant. It has antiandrogenic effect. However, the mechanism by which p,p'-DDE exposure causes male reproductive toxicity remains unknown. To elucidate the mechanism underpinning the testicular effects of p,p'-DDE, we sought to investigate apoptotic effects and mRNA expression of apoptosis-associated genes in the testis of pubertal rats, including Fas, FasL, calpain-1, cytochrome c, Bax, Bcl-w, Bak, and caspase-3, -8, -9, -12. Animals were administered with different doses of p,p'-DDE (0, 20, 60, 100 mg/kg body weight) every other day by intraperitoneal injection for 10 days. The results indicated that p,p'-DDE exposure at over 20 mg/kg body weight showed the induction of apoptotic cell death. p,p'-DDE could induce decrease in SOD and GSH-Px activity of serum in 60 mg/kg body weight group. Significant elevations in the mRNA levels of Fas, FasL, calpain-1, cytochrome c, Bax, Bak, and caspase-3, -8, -9, -12 were observed in testis of rat treated with p,p'-DDE. Taken together, these results lead us to speculate that in vivo exposure to p,p'-DDE might induce testicular apoptosis in pubertal rats through the involvement of Fas/FasL, mitochondria and endoplasmic reticulum-mediated pathways.

Influence of prenatal organohalogen levels on infant male sexual development: sex hormone levels, testes volume and penile length

BACKGROUND

Prenatal exposure to endocrine disruptors, like organohalogen compounds (OHCs), might be responsible for the increased aberrations in human male sexual development (hypospadias, cryptorchidism, testicular cancer and fall in sperm count) observed over the past decades. This development is established during fetal life, and reflected in sex hormone levels, testes volume and penile length post-partum. The present study investigates the correlation between prenatal OHC levels and male sexual development outcomes.

METHODS AND RESULTS

Levels of eight neutral [2,2'-bis-(4-chlorophenyl)-1,1'-dichloroethene (4,4'-DDE), 2,2',4,4',5,5'-hexachlorobiphenyl, 2,2',4,4'-tetrabromodiphenyl ether (BDE)-47, -99, -100, -153, -154 and 1,2,5,6,9,10-hexabromocyclododecane, HBCDD] and four phenolic [(pentachlorophenol (PCP), 4OH-CB-107 (4-hydroxy-2,3,3',4',5-pentachlorobiphenyl), -146 and -187)] OHCs were determined in 55 maternal serum samples taken at 35 weeks of pregnancy. Eight sex development-related hormones [testosterone, free testosterone, sex hormone-binding globulin (SHBG); LH, FSH, estradiol (E(2)), free E(2) (FE(2)) and inhibin B (InhB)] were determined in their sons at 3 months of age, and testes volume and penile length at 3 and 18 months of age. The following prenatal OHC levels correlated significantly with sex hormone levels: PCP with SHBG and InhB (ρ = 0.30 and -0.43, respectively), 4OH-CB-107 with testosterone (ρ = 0.31) and BDE-154 with FE(2), E(2) and InhB (ρ = 0.49, 0.54 and 0.34, respectively). BDE-154 levels correlated positively with testes volume at 18 months of age (ρ = 0.34).

CONCLUSIONS

Prenatal OHC exposure is correlated with aspects of sexual development outcome in boys up to 18 months of age.

p,p'-DDE induces testicular apoptosis in prepubertal rats via the Fas/FasL pathway

1,1-Dichloro-2,2 bis(p-chlorophenyl) ethylene (p,p'-DDE), the major metabolite of 2,2-bis(4-chlorophenyl)-1,1,1-trichloroethane (DDT), is a known persistent organic pollutant and male reproductive toxicant. It has antiandrogenic effect. However, the mechanism by which p,p'-DDE exposure causes male reproductive toxicity remains unknown. To elucidate the mechanism underpinning the testicular effects of p,p'-DDE, we sought to investigate Fas/FasL apoptotic pathway in the testis of prepubertal rats, including Fas, FasL, caspase-8, -3, and NF-kappaB. Animals were administered with different doses of p,p'-DDE (0, 20, 60, 100mg/kg b.wt) every other day by intraperitoneal injection for 10 days. The results indicated that p,p'-DDE exposure at over 20mg/kg b.wt showed the induction of apoptotic cell death. p,p'-DDE could induce increase in the MDA level, and decrease in SOD and GSH-Px activity. Significant elevations in the mRNA levels of Fas along with an increase in FasL, caspase-3, -8 were observed in 100mg/kg b.wt group. In protein level, p,p'-DDE could induce increase of FasL and reduction of procaspase-8. NF-kappaB p65 was activated by p,p'-DDE treatment in rat testis. In addition, the activities of caspase-3, -8 were increased in 100mg/kg b.wt group. Taken together, these results lead us to speculate that in vivo exposure to p,p'-DDE might induce testicular apoptosis in prepubertal rats through the Fas/FasL pathway.

p,p'-DDE induces apoptosis of rat Sertoli cells via a FasL-dependent pathway

One,1-dichloro-2,2 bis(p-chlorophenyl) ethylene (p,p′-DDE), the major metabolite of 2,2-bis(4-Chlorophenyl)-1,1,1-trichloroethane (DDT), is a known persistent organic pollutant and male reproductive toxicant. It has antiandrogenic effect. However, the mechanism by which p,p′-DDE exposure causes male reproductive toxicity remains unknown. In the present study, rat Sertoli cells were used to investigate the molecular mechanism involved in p,p′-DDE-induced toxicity in male reproductive system. The results indicated that p,p′-DDE exposure at over 30 μM showed the induction of apoptotic cell death. p,p′-DDE could induce increases in FasL mRNA and protein, which could be blocked by an antioxidant agent, N-acetyl-l-cysteine (NAC). In addition, caspase-3 and -8 were activated by p,p′-DDE treatment in these cells. The activation of NF-κB was enhanced with the increase of p,p′-DDE dose. Taken together, these results suggested that exposure to p,p′-DDE might induce apoptosis of rat Sertoli cells through a FasL-dependent pathway.

p,p'-DDE induces mitochondria-mediated apoptosis of cultured rat Sertoli cells

p,p'-Dichlorodiphenoxydichloroethylene (p,p'-DDE), the major metabolite of dichlorodiphenoxytrichloroethane (DDT), is a known persistent organic pollutant and male reproductive toxicant. However, the mechanism underlying male reproductive toxicity of p,p'-DDE remains limited. In the present study, Sertoli cells were used to investigate the molecular mechanism involved in p,p'-DDE's male reproductive toxicity. Results showed that p,p'-DDE exposure at over 30 microM showed induction of apoptotic cell death. p,p'-DDE could induce mitochondria-mediated apoptotic changes including elevation in reactive oxygen species (ROS) generation, decrease in mitochondrial membrane potential (DeltaPsi(m)), and release of cytochrome c into the cytosol, which could be blocked by antioxidant agent N-acetyl-l-cysteine (NAC). In addition, elevated ratios of Bax/Bcl-w and Bak/Bcl-w and cleavages of procaspase-3 and -9 were induced by p,p'-DDE treatment. All of the results suggested that ROS generation may play a critical role in the initiation of p,p'-DDE-induced apoptosis by mediation of the disruption of DeltaPsi(m), the release of cytochrome c into the cytosol and further the activation of caspase cascade.