Estrogenic alkylphenols induce cell death by inhibiting testis endoplasmic reticulum Ca(2+) pumps

Cocktail effects of tire wear particles leachates on diverse biological models: A multilevel analysis

Tire wear particles (TWP) stand out as a major contributor to microplastic pollution, yet their environmental impact remains inadequately understood. This study delves into the cocktail effects of TWP leachates, employing molecular, cellular, and organismal assessments on diverse biological models. Extracted in artificial seawater and analyzed for metals and organic compounds, TWP leachates revealed the presence of polyaromatic hydrocarbons and 4-tert-octylphenol. Exposure to TWP leachates (1.5 to 1000 mg peq L-1) inhibited algae growth and induced zebrafish embryotoxicity, pigment alterations, and behavioral changes. Cell painting uncovered pro-apoptotic changes, while mechanism-specific gene-reporter assays highlighted endocrine-disrupting potential, particularly antiandrogenic effects. Although heavy metals like zinc have been suggested as major players in TWP leachate toxicity, this study emphasizes water-leachable organic compounds as the primary causative agents of observed acute toxicity. The findings underscore the need to reduce TWP pollution in aquatic systems and enhance regulations governing highly toxic tire additives.

Nigella sativa seeds mitigate the hepatic histo-architectural and ultrastructural changes induced by 4-nonylphenol in Clarias gariepinus

Due to its prevalence in aquatic environments and potential cytotoxicity, 4-nonylphenol (4-NP) has garnered considerable attention. As a medicinal plant with numerous biological activities, Nigella sativa (black seed or black cumin) seed (NSS) is widely utilized throughout the world. Consequently, this study aimed to examine the potential protective effects of NSS against 4-NP-induced hepatotoxicity in African catfish (Clarias gariepinus). To achieve this objective, 18 fish (351 ± 3 g) were randomly divided into three equal groups for 21 days. The first group serves as a control which did not receive any treatment except the basal diet. The second and third groups were exposed to 4-NP at a dose of 0.1 mg L^-1 of aquarium water and fed a basal diet only or supplemented with 2.5% NSS, respectively. The histological, histochemical, and ultrastructural features of the liver were subsequently evaluated as a damage biomarker of the hepatic tissue. Our results confirmed that 4-NP was a potent hepatotoxic agent, as 4-NP-intoxicated fish exhibited many lesions. Steatohepatitis, ballooning degeneration, sclerosing cholangitis, and coagulative necrosis of melanomacrophagecenters (MMCs) were observed. Hemosiderin, lipofuscin pigments, and proliferation of fibroblasts, kupffer cells, and telocytes were also demonstrated in the livers of 4-NP-intoxicated fish. In addition, decreased glycogen content and increased collagen deposition were observed in the hepatic tissue. Hepatocytes exhibited ultrastructural alterations in the chromatin, rough endoplasmic reticulum, smooth endoplasmic reticulum, mitochondria, lysosomes, and peroxisomes. Co-administration of 2.5% NSS to 4-NP-intoxicated fish significantly reduced these hepatotoxic effects. It nearly preserved the histological, histochemical, and ultrastructural integrity of hepatic tissue.

High cytotoxicity of a degraded TBBPA, dibromobisphenol A, through apoptotic and necrosis pathways

Halogenated flame retardants comprising bisphenol A (BPA) derivatives, such as tetrabromobisphenol A (TBBPA), have been studied their adverse effects on human health. However, despite the fact that these halogenated BPAs are easily degraded in the environment, the risks to living organisms due to these degraded products have mostly been overlooked. To evaluate the potential toxicity of degraded TBBPAs and related compounds, we examined the cytotoxicity of halogenated bisphenol A derivatives possessing one to four halogen atoms in vitro. The results indicated that the degraded TBBPA derivatives exhibited strong cytotoxicity against HeLa cells than TBBPA. Interestingly, the di-halogenated BPA derivatives possessing two halogen atoms exhibited the strongest cytotoxicity among tested compounds. In addition, a lactate dehydrogenase release assay, fluorescence spectroscopy and flow cytometry results indicated that dibromo-BPA and diiodo-BPA induced both apoptotic and necrotic cell death by damaging the cell membranes of HeLa cells. Moreover, Escherichia coli growth was inhibited in the presence of dehalogenated TBBPA and related compounds. These findings suggest that halogenated BPA derivatives that leak from various flame-retardant-containing products require strict monitoring, as not only TBBPA but also its degraded products in environment can exert adverse effects to human health.

Association between urinary bisphenol analogue concentrations and lung cancer in adults: A case-control study

Elevated urinary bisphenol A (BPA) concentrations have been associated with lung cancer in humans. However, toxicological studies demonstrated that the proliferation of lung cancer cells was inhibited by BPA exposure. Therefore, it is still necessary to determine whether exposure to BPA and other bisphenol analogues (BPs) is associated with lung cancer in humans. In this study, 226 lung cancer patients and 243 controls were randomly recruited. Concentrations of three BPs in human urine were quantified and their relationships with the risk of human lung cancer were evaluated. BPA (mean 1.03 ng/mL, 0.87 μg/g Cre) was the predominant BP in human urine, followed by bisphenol S (BPS) (0.72 ng/mL, 0.53 μg/g Cre) and bisphenol F (0.32 ng/mL, 0.37 μg/g Cre). Significant correlations between creatinine-corrected urinary BPA concentrations and the lung cancer risk (odds ratio (OR) _adjusted = 1.28, 95% confidence interval (CI): 1.17, 1.40; P_trend = 0.04) were found using logistical regression analysis. Creatinine-corrected urinary concentrations of BPS in participants showed significant correlations with lung cancer (OR_adjusted = 1.23, 95% CI: 1.04, 1.59; P_trend = 0.01) in the adjusted model. In the stratification analysis, the significant correlation between urinary creatinine-corrected concentrations of BPA and the risk of lung cancer still observed in male participants (OR = 1.36, 95% CI: 1.09, 1.62, p = 0.040). This study demonstrates that elevated human exposure to BPA and BPS may be associated with the increased lung cancer risk.

Occurrence and tissue distribution of alkylphenols (APs) in selected waterbirds from the Southern Baltic

The aim of the present study was to determine the concentrations of nonylphenols (NPs) and 4-t-octylphenol (4tOP) in the muscles, liver, and kidneys of selected waterbird species. Three species with different feeding habits were selected, i.e., greater scaup (Aythya marila), great crested grebe (Podiceps cristatus), and great cormorant (Phalacrocorax carbo) to investigate the potential effects of diet on the level of contaminants tested. The determination and quantification of analytes were performed using gas chromatography with mass spectrometric detection (GC-MS). The highest NP concentrations were noted in the kidneys of greater scaups and great crested grebes (208.3 and 160.8 μg kg^-1 ww, resp.), which were six to fourteen-fold higher than those in the muscles (15.0 and 25.6 μg kg^-1 ww, resp.) and livers (22.9 and 13.8 μg kg^-1 ww, resp.) of these species. In greater scaups, the mean concentration of NPs in the livers was lower than in the muscles, while in great crested grebes, it was the opposite and higher concentrations were noted in the muscles. The mean concentrations of NPs in the muscles and livers of great cormorants were at similarly low levels (12.5 and 9.7 μg kg^-1 ww, resp.). The concentrations of 4tOP in all samples were low, ranging from <LOQ to 0.29 μg kg^-1 ww. The results of our study indicated that sex and diet did not affect the NP tissue concentrations in different waterbird species, but the phenological period (migration vs breeding) might influence the contamination levels in the kidneys.

4-[1-Ethyl-1-methylhexy]-phenol induces apoptosis and interrupts Ca2+ homeostasis via ROS pathway in Sertoli TM4 cells

Biological effect of an individual nonylphenol (NP) isomer extremely relies upon the side chain structure. This research was designed to evaluate the impact of NP isomer, 4-[1-ethyl-1-methylhexy]-phenol (NP₆₅), on Sertoli cells in vitro. Sertoli TM4 cells were exposed to various concentration (0, 0.1, 1, 10, or 20 μM) of NP₆₅ for 24 h, and the outcomes indicated that treatment of NP₆₅ induced reactive oxygen species (ROS) generation, oxidative stress, and apoptosis for Sertoli TM4 cells. In addition, it was found that NP₆₅ exposure affected homeostasis of Ca²⁺ in Sertoli TM4 cells by increasing cytoplasm [Ca²⁺]i, inhibiting Ca²⁺-ATPase activity and decreasing cyclic adenosine monophosphate (cAMP) concentration. Pretreatment with ROS scavenger, N-acetylcysteine (NAC), attenuated NP₆₅-induced oxidative stress as well as apoptosis for TM4 cells. Furthermore, NAC blocked NP₆₅-induced disorders of Ca²⁺ homeostasis by attenuating the growth of intracellular [Ca²⁺]i and the inhibition of Ca²⁺-ATPase and cAMP activities. Thus, we have demonstrated that NP₆₅ induced apoptosis as well as acted as a potent inhibitor of Ca²⁺-ATPase activity and resulted in disorder of Ca²⁺ homeostasis in Sertoli TM4 cells; ROS participated in the process. Our results supported the view that oxidative stress acted an essential role within the development of apoptosis and Ca²⁺ overload in TM4 cells as a consequence of NP₆₅ stimulation.

Regucalcin ameliorates Doxorubicin-induced cytotoxicity in Cos-7 kidney cells and translocates from the nucleus to the mitochondria

Doxorubicin (DOX) is a potent anti-cancer drug, which can have unwanted side-effects such as cardiac and kidney toxicity. A detailed investigation was undertaken of the acute cytotoxic mechanisms of DOX on kidney cells, using Cos-7 cells as kidney cell model. Cos-7 cells were exposed to DOX for a period of 24 hours over a range of concentrations and the LC50 was determined to be 7µM. Further investigations showed that cell death was mainly via apoptosis involving Ca2+ and caspase 9, in addition to autophagy. Regucalcin (RGN), a cytoprotective protein found mainly in liver and kidney tissues, was overexpressed in Cos-7 cells and shown to protect against DOX-induced cell death. Subcellular localization studies in Cos-7 cells showed RGN to be strongly correlated with the nucleus. However, upon treatment with DOX for 4 hours, which induced membrane blebbing in some cells, the localization appeared to be correlated more with the mitochondria in these cells. It is yet to be determined whether this translocation is part of the cytoprotective mechanism or a consequence of chemically-induced cell stress.

Nonylphenol exposure in Labeo rohita (Ham.): Evaluation of behavioural response, histological, haematological and enzymatic alterations

The impact of acute and chronic exposure of nonylphenol (NP) on behaviour, histopathology, haematology and biochemical parameters of Labeo rohita (Hamilton, 1822) was investigated in the current study. The 96 h LC₅₀ of NP for L. rohita was estimated to be 0.548 mg L^-1. Acute toxicity of NP induced several behavioural alternations. Further, sub-lethal NP exposure for a period of sixty days to 1/10th (0.0548 mg L^-1), 1/15th (0.0365 mg L^-1) and 1/20th (0.0274 mg L^-1) of 96 h LC₅₀ resulted a reduction in total erythrocyte count and haemoglobin content whereas the total leukocyte count was observed to increase significantly. Among the biochemical parameters, blood glucose level increased, but there was significant decrease in total serum protein, albumin and globulin level. Significant alterations occurred in the histological architecture of gill tissue in NP exposed groups. The catalase and superoxide dismutase activity in gill tissues were elevated significantly while the concentration dependent inhibition of acetylcholinesterase activity was observed on 20th, 40th and 60th day of NP exposure. An increased glutathione-S-transferase activity in gill tissue was also observed in NP exposed groups. The present ecotoxicological study provides a reliable indication for the obligation to control the use and safe disposal of NP.

The protective role of curcumin against toxic effect of nonylphenol on bone development

INTRODUCTION

In the study, it was aimed to investigate the possible protective effects of curcumin, a potent antioxidant, against the toxic effect of nonylphenol on bone development.

METHODS

Thirty pregnant female Wistar albino rats were used. The rats were randomly divided into the following five groups; the control group, corn oil group (150 µl/kg/day), nonylphenol group (50 µl/kg/day), curcumin group (100 mg/kg/day) and curcumin + nonylphenol group (100 mg/kg/day + 50 µl/kg/day). The doses were given by gavage from the 5th day to the 20th day of gestation. The fetuses were removed out on the 20th day of pregnancy by cesarean at the end of the study. After the sacrifice of the animals, double skeletal staining in front extremity (clavicula, scapula, humerus, radius, ulna) and hind extremity (femur, tibia, fibula), additionally histological and immunohistochemical examinations in femur bone were performed.

RESULTS

The nonylphenol group offspring have the lowest weights of fetuses and placenta, head-to-hip lengths, biparietal and occipitofrontal length, and also, bone length percentage and percentage of the ossification area in all measurements of the front extremity and hind extremity Interestingly, the groups treated with curcumin showed close to the control group in terms of double skeletal staining, histological, and immunohistochemical examinations.

CONCLUSIONS

Our findings demonstrated an association between bone development and exposure to nonylphenol. The findings suggest that curcumin treatments may be effective in accelerating bone formation.

The mechanism of cytotoxicity of 4-nonylphenol in a human hepatic cell line involves ER-stress, apoptosis, and mitochondrial dysfunction

4-Nonylphenol (4-NP) is an emerging environmental pollutant widely diffused in waters and sediments. It mainly derives from the degradation of alkyl phenol ethoxylates, compounds commonly employed as industrial surfactants. 4-NP strongly contaminates foods and waters for human use; thus, it displays a wide range of toxic effects not only for aquatic organisms but also for mammals and humans. After ingestion through the diet, it tends to accumulate in body fluids and tissues. One of the main organs where 4-NP and its metabolites are concentrated is the liver, where it causes, even at low doses, oxidative stress and apoptosis. In the present study, we analyzed the effects of 4-NP on a human hepatic cell line (HepG2) to deepen the knowledge of its cytotoxic mechanism. We found that 4-NP, in a range of concentration from 50 to 100 μM, significantly reduced cell viability; it caused a partial block of proliferation and induced apoptosis with activation of caspase-3 and overexpression of p53. Moreover, 4-NP induced-apoptosis seemed to involve both an ER-stress response, with the appearance of high level of GRP78, CHOP and the spliced XBP1, and a dysregulation of mitochondrial physiology, characterized by an overexpression of main markers of mitochondrial dynamics. Our data support the idea that a daily consumption of 4-NP-contaminated foods may lead to local damages at the level of gastrointestinal system, including liver, with negative consequences for the organ physiology.

Role of bisphenol A on calcium influx and its potential toxicity on the testis of Danio rerio

This study investigated the acute in vitro effect of low-concentration bisphenol A (BPA) on calcium (⁴⁵Ca²⁺) influx in zebrafish (Danio rerio) testis and examined whether intracellular Ca²⁺ was involved in the effects of BPA on testicular toxicity. In vitro studies on ⁴⁵Ca²⁺ influx were performed in the testes after incubation with BPA for 30 min. Inhibitors were added 15 min before the addition of ⁴⁵Ca²⁺ and BPA to testes to study the mechanism of action of BPA. The involvement of intracellular calcium from stores on lactate dehydrogenase (LDH) release and on triacylglycerol (TAG) content were carried out after in vitro incubation of testes with BPA for 1 h. Furthermore, gamma-glutamyl transpeptidase (GGT) and aspartate aminotransferase (AST) activities were analyzed in the liver at 1 h after in vitro BPA incubation of D. rerio. Our data show that the acute in vitro treatment of D. rerio testes with BPA at very low concentration activates plasma membrane ionic channels, such as voltage-dependent calcium channels and calcium-dependent chloride channels, and protein kinase C (PKC), which stimulates Ca²⁺ influx. In addition, BPA increased cytosolic Ca²⁺ by activating inositol triphosphate receptor (IP₃R) and inhibiting sarco/endoplasmic reticulum calcium ATPase (SERCA) at the endoplasmic reticulum, contributing to intracellular Ca²⁺ overload. The protein kinases, PKC, MEK 1/2 and PI3K, are involved in the mechanism of action of BPA, which may indicate a crosstalk between the non-genomic initiation effects mediated by PLC/PKC/IP₃R signaling and genomic responses of BPA mediated by the estrogen receptor (ESR). In vitro exposure to a higher concentration of BPA caused cell damage and plasma membrane injury with increased LDH release and TAG content; both effects were dependent on intracellular Ca²⁺ and mediated by IP₃R. Furthermore, BPA potentially induced liver damage, as demonstrated by increased GGT activity. In conclusion, in vitro effect of BPA in a low concentration triggers cytosolic Ca²⁺ overload and activates downstream protein kinases pointing to a crosstalk between its non-genomic and genomic effects of BPA mediated by ESR. Moreover, in vitro exposure to a higher concentration of BPA caused intracellular Ca²⁺-dependent testicular cell damage and plasma membrane injury. This acute toxicity was reinforced by increased testicular LDH release and GGT activity in the liver.

Oxidative stress in liver cell culture from mullet, Liza klunzingeri, induced by short-term exposure to benzo[a]pyrene and nonylphenol

The present investigation aimed to use primary liver cell culture obtained from mullet, Liza klunzingeri, to evaluate the toxic effects of benzo[a]pyrene (BaP) and nonylphenol (NP) on the antioxidant defense system. Liver samples taken from 20 L. klunzingeri were digested with 0.1% collagenase IV. The digested cells were then moved to Leibovitz L-15 culture medium and incubated at 25 °C for 2 weeks. 10^-5 mol/l of BaP and 10^-4 mol/l of NP were considered as the half maximal inhibitory concentration (IC50). Cells were then incubated with L-15 medium containing BaP (0[control], 10^-6,2 × 10^-6,3 × 10^-6 mol/l) and NP (0[control],10^-5,2 × 10^-5,3 × 10^-5 mol/l), and sampling was performed after 6, 12, and 24 h of incubation for measurement of catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GPx), lipid peroxidation (LPO), total antioxidant power, and total protein. The lowest concentration of BaP and NP did not have considerable toxic effects on cultivated hepatocytes. The activities of SOD, CAT, GPx, LPO, total antioxidant power, and total protein changed dose-dependently in cells treated with BaP and NP. In conclusion, based on the results, short-term exposure to BaP and NP induced the oxidative stress in cultivated liver cells of L. klunzingeri. The toxicity of both pollutants is mainly because of the induction of the reactive oxygen species (ROS), which lead to cell membrane disruption, damage of cellular metabolism, and interference with cellular macromolecules.

Evaluation of the Influence of Halogenation on the Binding of Bisphenol A to the Estrogen-Related Receptor γ

Halogenation of organic compounds is one the most important transformations in chemical synthesis and is used for the production of various industrial products. A variety of halogenated bisphenol analogs have recently been developed and are used as alternatives to bisphenol A (BPA), which is a raw material of polycarbonate that has adverse effects in animals. However, limited information is available on the potential toxicity of the halogenated BPA analogs. In the present study, to assess the latent toxicity of halogenated BPA analogs, we evaluated the binding and transcriptional activities of halogenated BPA analogs to the estrogen-related receptor γ (ERRγ), a nuclear receptor that contributes to the growth of nerves and sexual glands. Fluorinated BPA analogs demonstrated strong ERRγ binding potency, and inverse antagonistic activity, similar to BPA. X-ray crystallography and fragment molecular orbital (FMO) calculation revealed that a fluorine-substituted BPA analog could interact with several amino acid residues of ERRγ-LBD, strengthening the binding affinity of the analogs. The ERRγ binding affinity and transcriptional activity of the halogenated BPAs decreased with the increase in the size and number of halogen atom(s). The IC₅₀ values, determined by the competitive binding assay, correlated well with the binding energy obtained from the docking calculation, suggesting that the docking calculation could correctly estimate the ERRγ binding potency of the BPA analogs. These results confirmed that ERRγ has a ligand binding pocket that fits very well to BPA. Furthermore, this study showed that the binding affinity of the BPA analogs can be predicted by the docking calculation, indicating the importance of the calculation method in the risk assessment of halogenated compounds.

Sarco/Endoplasmic Reticulum Calcium ATPase Inhibitors: Beyond Anticancer Perspective

The sarco/endoplasmic reticulum calcium ATPase (SERCA), which plays a key role in the maintenance of Ca²⁺ ion homeostasis, is an extensively studied enzyme, the inhibition of which has a considerable impact on cell life and death decision. To date, several SERCA inhibitors have been thoroughly studied and the most notable one, a derivative of the sesquiterpene lactone thapsigargin, is gradually approaching a clinical application. Meanwhile, new compounds with SERCA-inhibiting properties of natural, synthetic, or semisynthetic origin are being discovered and/or developed; some of these might also be suitable for the development of new drugs with improved performance. This review brings an up-to-date comprehensive overview of recently discovered compounds with the potential of SERCA inhibition, discusses their mechanism of action, and highlights their potential clinical applications, such as cancer treatment.

Environmental Water Pollution, Endocrine Interference and Ecotoxicity of 4-tert-Octylphenol: A Review

4-tert-Octylphenol is a degradation product of non-ionic surfactants alkylphenol polyethoxylates as well as raw material for a number of industrial applications. It is a multimedia compound having been detected in all environmental compartments such as indoor air and surface waters. The pollutant is biodegradable, but certain degradation products are more toxic than the parent compound. Newer removal techniques from environmental waters have been presented, but they still require development for large-scale applications. Wastewater treatment by plant enzymes such as peroxidases offers promise in total removal of 4-tert-octylphenol leaving less toxic degradation products. The pollutant's endocrine interference has been well reported but more in oestrogens than in any other signalling pathways through which it is believed to exert toxicity on human and wildlife. In this paper we carried out a review of the activities of this pollutant in environmental waters, endocrine interference and relevance to its toxicities and concluded that inadequate knowledge of its endocrine activities impedes understanding of its toxicity which may frustrate current efforts at ridding the compound from the environment.

Antioxidant responses and DNA damage in primary hepatocytes of Van fish (Alburnus tarichi, Güldenstadt 1814) exposed to nonylphenol or octylphenol

Alkylphenols, a nonionic surface-active agent group, such as nonylphenol (NP) and octylphenol (OP) are important endocrine-disrupting chemicals (EDC). In this study, the dose- and time-dependent effects of NP and OP were investigated in the primary hepatocyte culture of Van Fish. In this study, samples were taken at different times and biochemical parameters were studied separately. The effects of the chemicals used on SOD, CAT, GSH-Px, MDA, and 8-OHdG were investigated in hepatocyte culture. The antioxidants SOD and CAT were observed to increase in all groups in the primary hepatocyte cultures at the 24th hour after NP and OP administration, whereas the GSH-Px level was observed to increase with OP at the 24th hour and with NP at the 48th hour. The MDA level was observed to reach its highest value for both chemicals in the 24th hour, and the 8-OHdG level was observed to increase toward the end of the follow-up time, compared to the control group (p < 0.05). In conclusion, different doses of NP and OP were found to induce an increase in the levels of antioxidants and the MDA level in Van Fish primary hepatocyte culture. DNA damage, on the other hand, may be considered to appear after longer-term exposure to NP and OP.

Protective effect of Lespedeza cuneata ethanol extract on Bisphenol A-induced testicular dysfunction in vivo and in vitro

PURPOSE

Bisphenol A (BPA) has been regarded as a possible risk factor for reproductive health. We examined potential reproductive health benefits of Lespedeza cuneata ethanol extract (LCE). Previously, Lespedeza cuneata showed many therapeutic effects. However, the protective effect of LCE on BPA-induced testicular dysfunction and its mechanisms have not been precisely studied.

METHODS

Mice were randomly divided into six groups (n = 7). Sperm counts and motility were measured by light microscope. Testosterone, total cholesterol, triglycerides, HDL, LDL-cholesterol, glucose, free fatty acids, hs-CRP, Angiotensinogen, Angiotensin II, GOT, GPT, TBARS, GSH, CAT, and SOD1 were measured in mouse serum. The potential protective effects of the LCE on mouse sertoli cells were evaluated.

RESULTS

Oral administration of LCE in BPA-exposed male mice restored testis weight, sperm count, motility, and testosterone levels by inhibiting markers in serum. In addition, treatment with LCE in BPA-treated TM4 sertoli cells recovered cell viability by attenuating Bax expression and activating caspase 3 and PARP.

CONCLUSIONS

These results indicate that LCE prevented BPA-induced testicular dysfunction and cell viability in BPA-treated TM4 sertoli cells. Our study also suggests that LCE has the potential to protect male reproductive health.

Cellular and molecular characterization of gametogenic progression in ex vivo cultured prepuberal mouse testes

BACKGROUND

Recently, an effective testis culture method using a gas-liquid interphase, capable of differentiate male germ cells from neonatal spermatogonia to spermatozoa has been developed. Nevertheless, this methodology needs deep analyses that allow future experimental approaches in basic, pathologic and/or reprotoxicologic studies. Because of this, we characterized at cellular and molecular levels the entire in vitro spermatogenic progression, in order to understand and evaluate the characteristics that define the spermatogenic process in ex vivo cultured testes compared to the in vivo development.

METHODS

Testicular explants of CD1 mice aged 6 and 10 days post-partum were respectively cultured during 55 and 89 days. Cytological and molecular approaches were performed, analyzing germ cell proportion at different time culture points, meiotic markers immunodetecting synaptonemal complex protein SYCP3 by immunocytochemistry and the relative expression of different marker genes along the differentiation process by Reverse Transcription - quantitative Polymerase Chain Reaction. In addition, microRNA and piwi-interactingRNA profiles were also evaluated by Next Generation Sequencing and bioinformatic approaches.

RESULTS

The method promoted and maintained the spermatogenic process during 89 days. At a cytological level we detected spermatogenic development delays of cultured explants compared to the natural in vivo process. The expression of different spermatogenic stages gene markers correlated with the proportion of different cell types detected in the cytological preparations.

CONCLUSIONS

In vitro progression analysis of the different spermatogenic cell types, from both 6.5 dpp and 10.5 dpp testes explants, has revealed a relative delay in relation to in vivo process. The expression of the genes studied as biomarkers correlates with the cytologically and functional detected progression and differential expression identified in vivo. After a first analysis of deep sequencing data it has been observed that as long as cultures progress, the proportion of microRNAs declined respect to piwi-interactingRNAs levels that increased, showing a similar propensity than which happens in in vivo spermatogenesis. Our study allows to improve and potentially to control the ex vivo spermatogenesis development, opening new perspectives in the reproductive biology fields including male fertility.

Using a liver cell culture from Epinephelus coioides as a model to evaluate the nonylphenol-induced oxidative stress

The present study aimed to use primary liver cell culture derived from the orange-spotted grouper, Epinephelus coioides, to assess the toxic effects of nonylphenol (NP) on the hepatocyte viability and the liver antioxidant system. E. coioides was selected due to its commercial importance. NP was used in this study because of its high potential of producing oxidative stress due to increased reactive oxygen species (ROS). A liver of E. coioides was digested with PBS containing 0.1% collagenase IV. The digested cells were moved to Leibovitz L-15 culture medium with 20% fetal bovine serum (FBS), 100IUmL^-1 penicillin, 100μgmL^-1 streptomycin. Aliquots of cell suspension were seeded as a monolayer into sterile 25cm² tissue culture flasks and incubated at 30°C for 14days. The medium, containing non-attached cells, was removed after 24 to 48h and a new medium was added. The IC50 of 10^-4molL^-1 was determined for nonylphenol using MTT assay. Cells were then incubated with L-15 medium containing 10^-5, 2×10^-5, 3×10^-5molL^-1 of NP and samples were taken after 6, 12 and 24h of incubation for analysis of LPO, SOD, CAT, GPx, LDH, AST, ALT, and ALP. Based on the results, the lowest concentration of NP was not markedly cytotoxic to primary hepatocytes and the cell sensitivity to NP increased dose-dependently. The activities of SOD, CAT and GPx decreased significantly, while activities of LPO, LDH, AST, ALT and ALP, increased significantly in a dose-related pattern in NP-treated cells. In conclusion, this study revealed that NP could induce the oxidative stress in cultivated hepatocytes of E. coioides during a short-term exposure. NP toxicity is mainly due to the induction of the reactive oxygen species (ROS), which lead to cell membrane disruption, damage of cellular metabolism, and interference with cellular macromolecules.

Mitochondrial Dysfunction and Ca2+ Overload in Injured Sertoli Cells Exposed to Bisphenol A

Bisphenol-A (BPA) is well known as one of endocrine-disrupting chemicals and testicular toxicant. In this present study, we determined whether BPA caused cell injury through mitochondria impairment and ROS overproduction. The cellular ROS production, mitochondrial ATP synthetase activity and Ca²⁺ concentration were examined. We have found BPA caused the cellular mitochondria dysfunction and followed by cell death in Sertoli cells. Moreover cytoplasm Ca²⁺ overload was also involved. Furthermore, pretreatment with N-acetyl-L-cysteine (NAC) could alleviate the damage by causing a remarkable decrease in ROS production and mitochondrial dysfunction. Collectively, our results showed that BPA exposure induced Sertoli cell apoptosis because of excessive ROS generation and mitochondrial dysfunction. © 2016 Wiley Periodicals, Inc. Environ Toxicol 32: 823-831, 2017.

In vitro effect of 4-nonylphenol on human chorionic gonadotropin (hCG) stimulated hormone secretion, cell viability and reactive oxygen species generation in mice Leydig cells

Nonylphenol is considered an endocrine disruptor and has been reported to affect male reproductive functions. In our in vitro study, we evaluated the effects of 4-nonylphenol (4-NP) on cholesterol levels, hormone formation and viability in cultured Leydig cells from adult ICR male mice. We also determined the potential impact of 4-NP on generation of reactive oxygen species (ROS) after 44 h of cultivation. The cells were cultured with addition of 0.04; 0.2; 1.0; 2.5 and 5.0 μg/mL of 4-NP in the present of 1 IU/mL human chorionic gonadotropin (hCG) and compared to the control. The quantity of cholesterol was determined from culture medium using photometry. Determination of hormone production was performed by enzyme-linked immunosorbent assay. Metabolic activity assay was used for quantification of cell viability. The chemiluminescence technique, which uses a luminometer to measure reactive oxygen species, was employed. Applied doses of 4-NP (0.04-5.0 μg/mL) slight increase cholesterol levels and decrease production of dehydroepiandrosterone after 44 h of cultivation, but not significantly. Incubation of 4-NP treated cells with hCG significantly (P < 0.001) inhibited androstenedione, but not testosterone, formation at the highest concentration (5.0 μg/mL). The viability was significantly (P < 0.05); (P < 0.001) increased at 1.0; 2.5 and 5.0 μg/mL of 4-NP after 44 h treatment. Furthermore, 44 h treatment of 4-NP (0.04-5.0 μg/mL) caused significant (P < 0.001) intracellular accumulation of ROS in exposed cells. Taken together, the results of our in vitro study reported herein is consistent with the conclusion that 4-nonylphenol is able to influence hormonal profile, cell viability and generate ROS.

Divergent Mechanisms Leading to Signaling Dysfunction in Embryonic Muscle by Bisphenol A and Tetrabromobisphenol A

Bisphenol A (BPA) and its brominated derivative tetrabromobisphenol A (TBBPA) are high production volume chemicals used in the manufacture of various consumer products. Although regarded as endocrine disruptors, these chemicals are suspected to exert nongenomic actions on muscle function that are not well understood. Using skeletal muscle microsomes, we examined the effects of BPA and TBBPA on ryanodine receptor type 1 (RyR1), dihydropyridine receptor (DHPR), and sarcoplasmic/endoplasmic reticulum Ca²⁺ ATPase (SERCA). We assessed the impact of these chemicals on Ca²⁺ dynamics and signaling in embryonic skeletal myotubes through fluorescent Ca²⁺ imaging and measurement of resting membrane potential (V_m). TBBPA activated RyR1 and inhibited DHPR and SERCA, inducing a net efflux of Ca²⁺ from loaded microsomes, whereas BPA exhibited little or no activity at these targets. Regardless, both compounds disrupted the function of intact myotubes. TBBPA diminished and eventually abrogated Ca²⁺ transients, altered intracellular Ca²⁺ equilibrium, and caused V_m depolarization. For some cells, BPA caused rapid Ca²⁺ transient loss without marked changes in cytosolic and sarcoplasmic reticulum Ca²⁺ levels, likely owing to altered cellular excitability as a result of BPA-induced V_m hyperpolarization. BPA and TBBPA both interfere with skeletal muscle function through divergent mechanisms that impair excitation-contraction coupling and may be exemplary of their adverse outcomes in other muscle types.

The role of Pten/Akt signaling pathway involved in BPA-induced apoptosis of rat Sertoli cells

Bisphenol-A (BPA), one of endocrine-disrupting chemicals, is a male reproductive toxicant. Previous studies have revealed the direct cytotoxicity of BPA in many cultured cells, such as mitotic aneuploidy in embryonic cells and somatic cells, and apoptosis in neurons and testicular Sertoli cells. To understand the action of BPA and assess its risk, the Pten/Akt pathway was investigated in cultured Sertoli cells to elucidate the mechanism of the reproductive effects of BPA. The results showed that over 50 μM BPA treatment could decrease the viability of Sertoli cells and cause more apoptosis. In addition, BPA could induce the increase in mRNA levels of Pten and Akt. The protein level of Pten was increased; however, the protein levels of phospho-Akt and procaspase-3 were decreased after BPA exposure. Taken together, observed results suggested that the Pten/Akt pathway might be involved in the apoptotic effects of BPA on Sertoli cells.

Mitogen-activated protein kinase and Akt pathways are involved in 4-n-nonyphenol induced apoptosis in mouse Sertoli TM4 cells

Nonylphenol (NP) is considered an important environmental toxicant, which may disrupt male reproductive system. The aim of this study was to investigate 4-n-nonylphenol (4-n-NP) induced apoptosis and its related mechanism in mouse Sertoli cell line, TM4 cells. Our results showed that NP treatment (0.1, 1, 10, 20 and 30 μM) decreased cell viability and induced apoptosis in the cells, accompanied by alteration of Bcl-2 family mRNA expression, activation of caspases-3, release of Ca(2+), and increase of reactive oxygen species (ROS) generation. Subsequently, it was found that the levels of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-PX) in the cells were markedly decreased, and maleic dialdehyde (MDA) content was increased by NP treatment. Then activation of the mitogen-activated protein kinases (MAPKs) pathways and inhibition of Akt pathway were simultaneously detected in NP challenged TM4 cells. Taken together, it was concluded that NP induced cytotoxicity and apoptosis in TM4 cells, and the apoptosis may be mediated via MAPKs and Akt pathways in addition to Ca(2+) release and ROS generation.

Bisphenol A induces oxidative stress and mitochondrial dysfunction in lymphoblasts from children with autism and unaffected siblings

Autism is a behaviorally defined neurodevelopmental disorder. Although there is no single identifiable cause for autism, roles for genetic and environmental factors have been implicated in autism. Extensive evidence suggests increased oxidative stress and mitochondrial dysfunction in autism. In this study, we examined whether bisphenol A (BPA) is an environmental risk factor for autism by studying its effects on oxidative stress and mitochondrial function in the lymphoblasts. When lymphoblastoid cells from autistic subjects and age-matched unaffected sibling controls were exposed to BPA, there was an increase in the generation of reactive oxygen species (ROS) and a decrease in mitochondrial membrane potential in both groups. A further subdivision of the control group into two subgroups-unaffected nontwin siblings and twin siblings-showed significantly higher ROS levels without any exposure to BPA in the unaffected twin siblings compared to the unaffected nontwin siblings. ROS levels were also significantly higher in the autism vs the unaffected nontwin siblings group. The effect of BPA on three important mtDNA genes-NADH dehydrogenase 1, NADH dehydrogenase 4, and cytochrome b-was analyzed to observe any changes in the mitochondria after BPA exposure. BPA induced a significant increase in the mtDNA copy number in the lymphoblasts from the unaffected siblings group and in the unaffected twin siblings group vs the unaffected nontwin siblings. In all three genes, the mtDNA increase was seen in 70% of the subjects. These results suggest that BPA exposure results in increased oxidative stress and mitochondrial dysfunction in the autistic subjects as well as the age-matched sibling control subjects, particularly unaffected twin siblings. Therefore, BPA may act as an environmental risk factor for autism in genetically susceptible children by inducing oxidative stress and mitochondrial dysfunction.

Analysis of Differentially Regulated Proteins in TM4 Cells Treated with Bisphenol A

BPA, bisphenol A, a monomer of epoxy resins and polycarbonate plastic, is used in many consumer products including the plastic linings of cans for food and babies' bottles. BPA has been reported to cause reproductive toxicity and affects cells in rats and mice at high doses. In this study, the effect of BPA on protein expression in TM4 cells (a mouse Sertoli cell line) known to play an essential role in Spermatogenesis was investigated by two-dimensional electrophoresis (2-DE). After 16 h exposure to 50, 100, 150, 200, and 250 microM of BPA, the viability of TM4 cells decreased to about 90, 85, 78, 55, and 30% of control respectively. Approximately 800 protein spots in TM4 cells were analyzed by 2-DE with pH 4-7 linear immobilized pH gradient (IPG) Dry Strip, and 11 proteins which showed significantly different expression levels were identified by matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF MS). Among these, HSP 27 and placental calcium binding protein may be proteins differentially expressed by BPA exposure.

Effects of leached components from silorane and methacrylate-based dental composites on the male mice reproductive system

BACKGROUND

This study aimed to investigate the potential toxic effects of leached components from either a methacrylate-based composite (Filtek Z250) or a silorane-based composite (Filtek P90) on the male mice reproductive system.

METHODS

Sixty adult Syrian male mice were divided into six groups. In test groups, leached components from composite specimens in artificial saliva or 75% aqueous ethanol solution were administered intragastrically daily for 28 days. The mice were then euthanized and the following reproductive parameters recorded: body weight changes; weight of paired testes; testis volume; Gonadosomatic Index (GSI); sperm motility; sperm viability; daily sperm production and epididymal sperm count.

RESULTS

There were no significant differences in body weight changes, weight of paired testes, GSI, testis volume, epididymal sperm count, and daily sperm production between groups. Sperm motility and sperm viability were significantly lower in all the test groups in comparison to the control groups. In addition, they were significantly lower in the test groups in which composite samples were immersed in aqueous ethanol solution.

CONCLUSIONS

Within the limitations of this study, the present data indicate that leached components from dental composites could affect sperm quality and therefore could potentially cause adverse effects on the male mice reproductive system.

The sarcoplasmic-endoplasmic reticulum Ca(2+)-ATPase (SERCA) is the likely molecular target for the acute toxicity of the brominated flame retardant hexabromocyclododecane (HBCD)

Hexabromocyclododecane (HBCD) is a widely utilised brominated flame retardant (BFR). It has been shown to bio-accumulate within organisms, including man, and possibly cause neurological disorders. The acute neurotoxicity of HBCD, and six other unrelated BFRs, were assessed in SH-SY5Y human neuroblastoma cells by 24h viability assays and HBCD proved to be the most lethal (LC50, 3μM). In addition, the effects of these BFRs were also assessed for their potency at inhibiting the sarcoplasmic-endoplasmic reticulum Ca(2+) ATPase (SERCA) derived from the SH-SY5Y cells and again HBCD was the most potent (IC50, 2.7μM). The data for the other BFRs tested showed a direct correlation (coefficient 0.94) between the potencies of inducing cell death and inhibiting the Ca(2+) ATPase, indicating that SERCA is likely to be the molecular target for acute toxicity. Mechanistic studies of HBCD on the Ca(2+) ATPase suggest that it affects ATP binding, phosphorylation as well as the E2 to E1 transition step.

A systematic review of Bisphenol A "low dose" studies in the context of human exposure: a case for establishing standards for reporting "low-dose" effects of chemicals

Human exposure to the chemical Bisphenol A is almost ubiquitous in surveyed industrialized societies. Structural features similar to estrogen confer the ability of Bisphenol A (BPA) to bind estrogen receptors, giving BPA membership in the group of environmental pollutants called endocrine disruptors. References by scientists, the media, political entities, and non-governmental organizations to many toxicity studies as "low dose" has led to the belief that exposure levels in these studies are similar to humans, implying that BPA is toxic to humans at current exposures. Through systematic, objective comparison of our current, and a previous compilation of the "low-dose" literature to multiple estimates of human external and internal exposure levels, we found that the "low-dose" moniker describes exposures covering 8-12 orders of magnitude, the majority (91-99% of exposures) being greater than the upper bound of human exposure in the general infant, child and adult U.S. Population. "low dose" is therefore a descriptor without specific meaning regarding human exposure. Where human exposure data are available, for BPA and other environmental chemicals, reference to toxicity study exposures by direct comparison to human exposure would be more informative, more objective, and less susceptible to misunderstanding.

Structural requirements for inhibitory effects of bisphenols on the activity of the sarco/endoplasmic reticulum calcium ATPase

Bisphenols (BPs) are a class of small organic compounds with widespread industrial applications. Previous studies have identified several BPs that interfere with the activity of the ion-translocating enzyme sarco/endoplasmic reticulum calcium ATPase (SERCA). In order to define the molecular determinants of BP-mediated SERCA inhibition, we conducted enzyme activity assays with rabbit SERCA to determine the inhibitory potencies of 27 commercially available BPs, which were the basis for structure-activity relationships. The most potent BPs inhibited SERCA at low micromolar concentrations and carried at their two phenyl rings multiple non-polar substituents, such as small alkyl groups or halides. Furthermore, the presence of methyl groups or a cyclohexyl group at the central carbon atom connecting the two phenyl moieties correlated with good potencies. For a characterization and visualization of enzyme/inhibitor interactions, molecular docking was performed, which suggested that hydrogen bonding with Asp254 and hydrophobic interactions were the major driving forces for BP binding to SERCA. Calcium imaging studies with a selection of BPs showed that these inhibitors were able to increase intracellular calcium levels in living human cells, a behavior consistent with that of a SERCA inhibitor.

The effect of nonylphenol on the motility and viability of bovine spermatozoa in vitro

The objective of this in vitro study was to determine the effect of nonylphenol (NP) as an environmental toxicant on the spermatozoa motility and viability. The dose- and time-dependent effect of nonylphenol (1, 10, 100 and 200 μg/mL) dissolved either in 0.1% dimethyl sulfoxide (DMSO) or 0.1% ethanol (ETOH) on the motility and viability of bovine spermatozoa, as a cell model, during several time periods (0 h, 2 h, 4 h and 6 h) were examined. The motility of spermatozoa was determined by the Sperm Vision(TM) CASA (Computer Assisted Semen Analyzer) system. The results showed decreased spermatozoa motility in all experimental groups with the addition of NP dissolved in 0.1% DMSO and 0.1% ETOH (P < 0.001 and P < 0.05). The lowest spermatozoa motility was found at doses > 100 μg/mL of NP in comparison with the control group. The viability of bovine spermatozoa detected by the MTT cytotoxicity assay was decreased significantly (P < 0.001) in all experimental groups with NP dissolved in 0.1% ETOH. The viability in groups with NP dissolved in 0.1% DMSO was significantly (P < 0.05) decreased at 1 μg/mL of NP and significantly decreased (P < 0.001) at doses > 10 μg/mL of NP. After 6 h of culture the MTT assay proved a negative effect of all NP doses the on cell viability. The obtained data clearly indicate the negative effect of NP as an endocrine disruptor on spermatozoa motility and viability, which should be seriously considered in the case of exposure to NP in animals and humans and as a reason of male reproductive dysfunction.

Sophoridine exerts an anti-colorectal carcinoma effect through apoptosis induction in vitro and in vivo

AIMS

To further investigate the anti-colorectal carcinoma (CRC) effect of Sophoridine (SRI) which is a quinolizidine alkaloid extracted from a traditional Chinese medicine (TCM) Sophora alopecuroides L. and detect the mechanism involved, provide some basis for the development of S. alopecuroides L.

MAIN METHODS

The anti-proliferation of SRI in human colorectal cells SW480 were detected by 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide(MTT) assay. The potential mechanism of anti-proliferation was also investigated using apoptosis assays. The rate of apoptosis cells was detected also. The apoptosis-related proteins cysteinyl aspartate specific protease (caspase), caspase-3, caspase-7, caspase-9, and poly-ADP-ribose-poly-merase (PARP) were determined by western blotting analysis. In animal studies, nude mice were subcutaneously injected with SW480 cells in the armpit to establish the xenograft tumors and administrated with different drugs (control, 5-Fu, SRI H, and SRI L). The general state of health of the mice and the growth of tumors were observed and the inhibitory rate was calculated. The pathology and ultrastructure of xenograft tumors treated with SRI were observed also.

KEY FINDINGS

SRI significantly inhibited the growth of SW480 cells, and the administration of SRI significantly inhibited the growth of xenograft tumors without apparent toxicity. SRI's mechanism of action involved the induction of apoptosis.

SIGNIFICANCE

These results suggest that SRI produces obvious anti-tumor effects in vitro and in vivo. It supports the viability of developing SRI as a novel therapeutic prodrug for CRC treatment, as well as providing a method for identifying new anti-tumor drugs in TCM.

Effects of 17α-ethynylestradiol and nonylphenol on liver and gonadal apoptosis and histopathology in Chalcalburnus tarichi

Chalcalburnus tarichi is an endemic cyprinid fish living in the Lake Van basin located in the Eastern Turkey. Fish (3+ ages) were exposed to 17α-ethynylestradiol (EE(2); 1, 10, 100 ng L(-1); nominal concentrations) and nonylphenol (NP; 10, 60, 200 μg L(-1) ; nominal concentrations) for 32 days under semistatic daily renewal conditions. The exposure period was followed by an evaluation of liver and gonadal apoptosis and gonad histopathology in males and females. Exposure to the highest concentrations of EE(2) (100 ng L(-1)) and NP (200 μg L(-1) ) caused significant increases in the extent of apoptosis in liver and gonads. Treatment with 100 ng L(-1) of EE(2) and 200 μg L(-1) NP increased the number of TUNEL positive hepatocytes significantly in both sexes compared to controls. The rates of apoptosis in testicular germ cells and ovarian follicular cells were significantly greater at the same concentrations. Exposure to EE(2) (100 ng L(-1)) and NP (60 and 200 μg L(-1)) caused thickening of interstitial connective tissue (fibrosis) in the seminiferous tubule wall and testis-ova formation in males. In females treated with 100 ng L(-1) EE(2) , increased percentage of atretic ooctytes and fibrotic areas in the ovarian somatic stromal tissue were found in the ovaries. Increase in atresia, without a statistical significance, and fibrotic stromal tissue were also noted in 60 and 200 μg L(-1) NP treatments. Results suggest that EE(2) - and NP-dependent hepatotoxicity and gonadotoxicity are causally related to the increase in apoptosis in C. tarichi.

In vitro effects of nonylphenol on functional responses of haemocytes of the colonial ascidian Botryllus schlosseri

The effects of nonylphenol (NP) on functional responses of haemocytes of the colonial ascidian Botryllus schlosseri were evaluated. Haemocytes were exposed to 0.1, 1 and 10 μM NP and the effects on haemocyte viability, adhesion, morphology, lysosomal membrane stability, phagocytic activity and early apoptosis were evaluated. Haemocyte viability and adhesion were not affected by NP. Phagocytic activity and the amoebocytic index decreased significantly at all the concentrations tested, while exposure of haemocytes to 1 and 10 μM NP caused a significant increase in the diffusion of Neutral Red into the cytosol. The percentage of cells positive to Annexin-V (indicative of early apoptosis) increased significantly at 1 and 10 μM NP. Results obtained suggested a relationship between NP and alterations in functional responses of haemocytes in B. schlosseri. Biomarkers measured resulted sensitive, rapid and reproducible, even if their responsiveness will be evaluated after in vivo exposure of animals to NP.

miRNA regulation of cytotoxic effects in mouse Sertoli cells exposed to nonylphenol

BACKGROUND

It is known that some environmental chemicals affect the human endocrine system. The harmful effects of endocrine disrupting chemical (EDC) nonylphenol (NP) have been studied since the 1980s. It is known that NP adversely affects physiological functions by mimicking the natural hormone 17 beta-estradiol. In the present study, we analyzed the expression of miRNAs and their target genes in mouse Sertoli TM4 cells to better understand the regulatory roles of miRNAs on Sertoli cells after NP exposure.

METHODS

Mouse TM4 Sertoli cells were treated with NP for 3 or 24 h, and global gene and miRNA expression were analyzed using Agilent mouse whole genome and mouse miRNA v13 arrays.

RESULTS

We identified genes that were > 2-fold differentially expressed in NP-treated cells and control cells (P < 0.05) and analyzed their functions through Gene Ontology analysis. We also identified miRNAs that were differentially expressed in NP-treated and control cells. Of the 186 miRNAs the expression of which differed between NP-treated and control cells, 59 and 147 miRNAs exhibited 1.3-fold increased or decreased expression at 3 and 24 h, respectively. Network analysis of deregulated miRNAs suggested that Ppara may regulate the expression of certain miRNAs, including miR-378, miR-125a-3p miR-20a, miR-203, and miR-101a, after exposure to NP. Additionally, comprehensive analysis of predicted target genes for miRNAs showed that the expression of genes with roles in cell proliferation, the cell cycle, and cell death were regulated by miRNA in NP-treated TM4 cells. Levels of expression of the miRNAs miR-135a* and miR-199a-5p were validated by qRT-PCR. Finally, miR-135a* target gene analysis suggests that the generation of reactive oxygen species (ROS) following exposure to NP exposure may be mediated by miR-135a* through regulation of the Wnt/beta-catenin signaling pathway.

CONCLUSIONS

Collectively, these data help to determine NP's actions on mouse TM4 Sertoli cells and increase our understanding of the molecular mechanisms underlying the adverse effects of xenoestrogens on the reproductive system.

A diversity of SERCA Ca2+ pump inhibitors

The SERCA (sarcoplasmic/endoplasmic reticulum Ca2+-ATPase) is probably the most extensively studied membrane protein transporter. There is a vast array of diverse inhibitors for the Ca2+ pump, and many have proved significant in helping to elucidate both the mechanism of transport and gaining conformational structures. Some SERCA inhibitors such as thapsigargin have been used extensively as pharmacological tools to probe the roles of Ca2+ stores in Ca2+ signalling processes. Furthermore, some inhibitors have been implicated in the cause of diseases associated with endocrine disruption by environmental pollutants, whereas others are being developed as potential anticancer agents. The present review therefore aims to highlight some of the wide range of chemically diverse inhibitors that are known, their mechanisms of action and their binding location on the Ca2+ ATPase. Additionally, some ideas for the future development of more useful isoform-specific inhibitors and anticancer drugs are presented.

In vitro assessment of reproductive toxicity on rats induced by organic contaminants of source water

The safety of drinking water attracts more and more attention these years. This study focused on the reproductive toxicity of source water in Jiangsu Province, China. The organic contaminants of source water are capable of bioaccumulating and cause health effects on human beings. The toxicological tests on Spermatogenic cells, Sertoli cells and Leydig cells of male rats showed that source water extracts can reduce testicular cells membrane integrity and depress cell viability significantly. Among these testicular cells, Leydig cells are most sensitive to organic contaminants and the testosterone secretion of Leydig cells is evidently disturbed correspondingly. The phenols in the source water may be chiefly responsible for the reproductive toxicity. These data indicated that chronic reproductive toxicity of source water cannot be overlooked and action should be taken to protect human health from the threat of organic pollution of source water.

Bisphenol A effect on glutathione synthesis and recycling in testicular Sertoli cells

BACKGROUND AND OBJECTIVE

Controversial effects of bisphenol A (BPA) have been reported on testicular function. These differences might reflect dissimilar exposure conditions. Dose responses to toxicants may be non-linear, e.g. U-shaped, with effects at low and at high levels of exposure and lower or inexistent effects at intermediate levels. Sertoli cells produce high levels of glutathione (GSH) as a cell defense mechanism. In this study, we addressed the question whether the exposure to different doses of BPA could influence Sertoli cell GSH synthesis and recycling.

MATERIALS AND METHODS

Primary Sertoli cell cultures were exposed to various doses of BPA (0.5 nM-100 μM). Cell viability was measured as an outcome of toxic effect. GSH cell content was determined to evaluate cell response to toxicant exposure. Glutamate-cysteine ligase catalytic (GCLC) and modulatory (GCLM) subunit expression were assessed to estimate GSH synthesis, and GSH reductase (GR) expression to estimate GSH recycling.

RESULTS

BPA 100 μM, but not lower doses, decreased cell viability. BPA 10 and 50 μM, but not lower doses, induced an increment in Sertoli cell GSH levels, due to a rapid upregulation of GCLC and GR and a slower upregulation of GCLM.

CONCLUSIONS

High doses of BPA are deleterious for Sertoli cells. Intermediate doses do not affect Sertoli cell viability and increase cell content of GSH owing to increased GSH synthesis and recycling enzyme expression. Lower doses of BPA are not capable of eliciting a cell defense response. These observations may explain a non-linear dose response of Sertoli cells to BPA.

Increase of anteroventral periventricular kisspeptin neurons and generation of E2-induced LH-surge system in male rats exposed perinatally to environmental dose of bisphenol-A

Perinatal exposure to environmental levels of bisphenol-A (BPA) impairs sexually dimorphic behaviors in rodents. Kisspeptin neurons in anteroventral periventricular nucleus (AVPV), which plays an important role in the activation of GnRH neurons and the initiation of LH-surge, have been suggested to be sexual dimorphism in rats. This study focused on exploring the influence of a perinatal exposure to an environmental dose of BPA on the development and maturation of male AVPV kisspeptin neurons and hypothalamus-pituitary-gonadal axis. Female rats were injected sc with 2 μg BPA/kg·d from gestation d 10 through lactation d 7. Anatomical and functional changes in AVPV kisspeptin neurons and hypothalamus-pituitary-gonadal axis were examined in prepubertal, pubertal, and adult male rats exposed perinatally to BPA (BPA-rats). Here, we show that in postnatal d (PND)30/50/90 BPA-rats, the number of AVPV kisspeptin-immunoreactive cells was persistently increased in comparison with age-matched control male rats. The number of GnRH-immunoreactive cells in PND30 BPA-rats declined approximately 40% compared with control male rats, whereas that in PND50/90 BPA-rats was increased in a G protein-coupled receptor 54-dependent manner. Estradiol could induce a stable LH-surge in PND90 BPA-rats and control female rats, which was sensitive to the G protein-coupled receptor 54 inhibitor. In PND30/50 BPA-rats, plasma level of LH was higher, but the level of testosterone was lower than control male rats. These findings provide evidence that perinatal exposure to an environmental dose of BPA causes a sustained increase in AVPV kisspeptin neurons in male rats, leading to the generation of estradiol-induced LH-surge system.