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1.
Ecotoxicology ; 29(2): 163-174, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31938948

RESUMO

Perfluorooctanoic acid's (PFOA) widespread use, presence and persistence in the aquatic environment has led to an increasing number of studies focusing on its toxicological effects. In Australia, PFOA has been detected in the aquatic environment, however its effects on Australian native fauna are unknown. In this study, male Australian native fish Murray River rainbowfish (Melanotaenia fluviatilis) were exposed to four different concentrations of PFOA (0.01, 0.1, 1 and 10 mg L-1). Variations in thyroid hormones (Triiodothyronine (T3)/Thyroxine (T4)) and the presence of vitellogenin were determined in plasma. Oxidative stress responses were evaluated in gills and liver. Exposure of male fish to PFOA resulted in altered T3/T4 ratios and the presence of vitellogenin in the plasma. Activities of catalase (CAT) and glutathione- S-transferase (GST) were significantly increased in the gills and significantly reduced in the liver. Lipid peroxidation was observed in both tissues showing that vital organs could not neutralize the peroxides generated by oxidative stress resulting from exposure to PFOA. In natural populations exposed to PFOA, such hormonal disturbances can have negative effects, notably through altered capacity to respond to changes in environmental conditions.


Assuntos
Caprilatos/toxicidade , Fluorcarbonetos/toxicidade , Glândula Tireoide/efeitos dos fármacos , Poluentes Químicos da Água/toxicidade , Animais , Austrália , Catalase/metabolismo , Peixes , Peroxidação de Lipídeos/efeitos dos fármacos , Estresse Oxidativo , Glândula Tireoide/fisiologia , Vitelogeninas/metabolismo
2.
Chemosphere ; 241: 125037, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31683436

RESUMO

This study investigated the effects of microcystin (MC) on the regulation of thyroid hormone (TH) metabolism in juvenile zebrafish exposed to MC-LR. The results showed that acute MC-LR exposure at concentrations ranging from 50 µg/L to 400 µg/L led to significant reductions in thyroxine (T4) and triiodothyronine (T3) levels in juvenile zebrafish. The transcription levels of genes involved in TH synthesis, such as corticotropin-releasing hormone (crh), thyroid-stimulating hormone (tsh), thyroid peroxidase (tpo) and transthyretin (ttr), were significantly decreased followed by an increase after MC-LR exposure. Transcription of the TH nuclear receptors (tr-α and tr-ß) was significantly reduced during the exposure period. Moreover, the activities of iodothyronine deiodinase type Ⅰ (ID1) and iodothyronine deiodinase type Ⅱ (ID2) showed initially decreased and then increased trend, while the activity of iodothyronine deiodinase type Ⅲ (ID3) significantly decreased during MC-LR exposure. In addition, the effect of MC-LR on deiodinase activities and T4 contents were important causes of the decreased T3 at the early exposure stage. These results indicated that acute MC-LR exposure significantly interfered with the transcription of genes related to TH synthesis, transport and metabolism, and affected normal function of the thyroid which leads to decrease of T4 and T3 in juvenile zebrafish. Therefore, the thyroid function is susceptible to interference by MC-LR, and it may cause adverse effects on the growth and development of juvenile zebrafish.


Assuntos
Iodeto Peroxidase/metabolismo , Microcistinas/toxicidade , Hormônios Tireóideos/metabolismo , Transcrição Genética/efeitos dos fármacos , Peixe-Zebra/metabolismo , Animais , Toxinas Bacterianas/toxicidade , Iodeto Peroxidase/genética , Microcistinas/metabolismo , Fosfoproteínas Fosfatases/toxicidade , Glândula Tireoide/efeitos dos fármacos , Receptores beta dos Hormônios Tireóideos/metabolismo , Peixe-Zebra/genética , Proteínas de Peixe-Zebra/genética , Proteínas de Peixe-Zebra/metabolismo
3.
Environ Pollut ; 259: 113868, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31887590

RESUMO

Although the coexistence of heavy metals and environmental hormones always occur in aquatic environment, the information of the combined impacts remains unclear. To explore the multi-generational toxicity of cadmium (Cd) and tributyltin (TBT), adult zebrafish (Danio rerio) (F0) were exposed to different treated groups (100 ng/l Cd, 100 ng/l TBT and their mixture) for 90 d, with their offspring (F1 and F2) subsequently reared in the same exposure solutions corresponding to their parents. Both developmental neurotoxicity and thyroid disturbances were examined in the three (F0, F1, and F2) generations. Our results showed that co-exposure to Cd and TBT induced the developmental neurotoxicity in F1 and F2 generations, reflected by the significant lower levels of neurotransmitters (dopamine and serotonin) and the inhibited acetylcholinesterase (AChE) activities. And the thyroid endocrine disruption were observed in the two-generations larval offspring by parental exposure to Cd and/or TBT, including the significantly decreasing levels of thyroid hormones and the down-regulated the expression of genes involved in the hypothalamus-pituitary-thyroid axis, compared to the control. Additional, the embryonic toxicity and growth inhibition were also determined in the fish larvae. Overall, this study examined the impacts of parental co-exposure to Cd and TBT, with regard to developmental inhibition, nervous system damage and endocrine disruption, which highlighted that co-exposure influences are complicated and need to be considered for accurate environmental risk assessment.


Assuntos
Cádmio , Glândula Tireoide , Compostos de Trialquitina , Poluentes Químicos da Água , Peixe-Zebra , Animais , Cádmio/toxicidade , Embrião não Mamífero/efeitos dos fármacos , Disruptores Endócrinos/toxicidade , Glândula Tireoide/efeitos dos fármacos , Compostos de Trialquitina/toxicidade , Poluentes Químicos da Água/toxicidade
4.
Chemosphere ; 240: 124936, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31568941

RESUMO

Triphenyltin (TPT) is widely used and commonly found in a water environment, so its effects on aquatic systems are of great concern. This study aimed to reveal the effects of chronic parental exposure of TPT on thyroid disruption and growth inhibition in zebrafish. Adult zebrafish (F0 generation) were exposed to environmentally relevant concentrations (1, 10, and 100 ng/L) of TPT for 60 days, and the larvae (F1 generation) were tested without TPT treatment. Results demonstrated that parental exposure to TPT disrupts thyroid function in zebrafish offspring: serum thyroxine (T4) significantly decreased, while serum 3,5,3'-triiodothyronine (T3) increased, and several genes involved in the hypothalamic-pituitary-thyroid (HPT) axis were down-regulated. In addition, we observed developmental abnormalities in the larvae, demonstrated by a significantly altered hatching rate, malformation rate, body length, heart rate, and survival rate, as well as down-regulation of genes involved in the growth hormone/insulin-like growth factor (GH/IGF) axis. Therefore, parental exposure to TPT induces toxicity in fish offspring through perturbation of the HPT and GH/IGF axes.


Assuntos
Larva/crescimento & desenvolvimento , Compostos Orgânicos de Estanho/toxicidade , Praguicidas/toxicidade , Glândula Tireoide/patologia , Poluentes Químicos da Água/toxicidade , Animais , Feminino , Hormônio do Crescimento/genética , Hormônio do Crescimento/metabolismo , Larva/efeitos dos fármacos , Masculino , Exposição Materna/efeitos adversos , Exposição Paterna/efeitos adversos , Somatomedinas/genética , Somatomedinas/metabolismo , Glândula Tireoide/efeitos dos fármacos , Tiroxina/sangue , Tri-Iodotironina/sangue , Peixe-Zebra/embriologia
5.
Mar Pollut Bull ; 145: 174-184, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31590774

RESUMO

Elevated concentrations of persistent organic pollutants (POPs) and emerging halogenated flame retardants (HFRs) have been reported in tissues of the endangered St. Lawrence Estuary (Canada) beluga population as well as in minke whales visiting that same feeding area. This study examined the linkages between blubber concentrations of POPs and emerging HFRs, and transcription in skin of genes involved in the regulation of thyroid and steroid axes in belugas and minke whales from the St. Lawrence Estuary. In belugas, concentrations of PCBs, OCs and hexabromobenzene (HBB) were positively correlated with the transcription of thyroid- and/or steroid-related genes, while Dec-604 CB concentrations were negatively associated with the transcription of glucocorticoid and thyroid genes. In minke whales, PBDE concentrations changed positively with Esrß transcript levels and HBB concentrations negatively with Nr3c1 transcripts. Present results suggest that several biological functions including reproduction and energetic metabolism may represent potential targets for organohalogens in these whales.


Assuntos
Beluga/genética , Regulação da Expressão Gênica/efeitos dos fármacos , Baleia Anã/genética , Poluentes Químicos da Água/toxicidade , Tecido Adiposo/química , Animais , Beluga/metabolismo , Ecotoxicologia , Estuários , Feminino , Retardadores de Chama/análise , Retardadores de Chama/toxicidade , Masculino , Baleia Anã/metabolismo , Bifenilos Policlorados/análise , Bifenilos Policlorados/toxicidade , Quebeque , Esteroides/metabolismo , Glândula Tireoide/efeitos dos fármacos , Poluentes Químicos da Água/análise
6.
Ecotoxicol Environ Saf ; 186: 109776, 2019 Dec 30.
Artigo em Inglês | MEDLINE | ID: mdl-31606647

RESUMO

In the present study, to evaluate neurobehavioral toxicity and the thyroid-disrupting effects of environmental levels of triphenyltin (TPT), the zebrafish larvae were exposed to 1, 10 and 100 ng/l TPT. In the neurobehavioral assay, increased levels of dopamine and serotonin, decreased content of nitric oxide, inhibited activities of acetylcholinesterase and monoamine oxidase were observed in the whole body of zebrafish larvae after TPT treatment, as well as the serious abnormal non-reproductive behavior. Moreover, the whole-body the T4 levels were markedly decreased significantly, whereas T3 levels were not significantly changed under TPT stress. In addition, TPT exposure significantly changed the expression levels of genes related to thyroid system, including corticotropin-releasing hormone gene crh, thyroid-stimulating hormone gene tshß, thyroglobulin gene tg, sodium/iodide symporter gene nis, thyroid hormone nuclear receptor trα, isoform trß, types I deiodinase gene dio1and types II deiodinase gene dio2. The regulated responsiveness of thyroid hormone and related genes expression levels suggested that TPT could induce the thyroid disrupting effects in zebrafish larvae. Therefore, our results provide new aspects of TPT as an endocrine disrupting chemical.


Assuntos
Comportamento Animal/efeitos dos fármacos , Disruptores Endócrinos/toxicidade , Compostos Orgânicos de Estanho/toxicidade , Glândula Tireoide/efeitos dos fármacos , Peixe-Zebra/metabolismo , Animais , Hormônio Liberador da Corticotropina/genética , Regulação da Expressão Gênica/efeitos dos fármacos , Iodeto Peroxidase/genética , Larva/efeitos dos fármacos , Larva/metabolismo , Glândula Tireoide/metabolismo , Hormônios Tireóideos/metabolismo , Tireotropina/genética , Proteínas de Peixe-Zebra/metabolismo
7.
Environ Int ; 133(Pt A): 105179, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31627134

RESUMO

Polybrominated diphenyl ethers (PBDEs), which are persistent organic pollutants, affect thyroid function. Human exposure to decabromodiphenyl ethane (DBDPE), which has a similar structure to PBDEs, has recently increased, and the health effects of DBDPE have not been well studied. The objective of this study was to determine whether human exposure to DBDPE was associated with thyroid hormone levels in adults from a DBDPE manufacturing area. Three hundred-two blood samples were collected from two populations in the largest DBDPE manufacturing area located in North China: 133 DBDPE occupationally exposed workers from a DBDPE manufacturing plant and 169 non-DBDPE occupationally exposed residents from a nearby food processing plant. The levels of DBDPE, and thyroid function parameters [total thyroxine (TT4), free T4 (FT4), total triiodothyronine (TT3), free T3 (FT3), thyroid-stimulating-hormone (TSH), thyroglobulin antibody (TG-Ab), and thyroid peroxidase antibody (TPO-Ab)] were measured in serum samples. Serum concentrations of DBDPE ranged from 3.148 to 54,360 ng g-1 lipid weight (lw), with a geometric mean of 332.6 ng g-1 lw. A 10-fold increase in the DBDPE concentration was associated with increase of 4.73 nmol L-1 [95% confidence interval (CI): 2.75, 6.71] TT4 and 0.046 nmol L-1 TT3 [95% CI: 0.012, 0.081], corresponding to increases of approximately of 4.73% (95% CI: 2.75%-6.71%) and 2.38% (95% CI: 0.62%-4.20%), respectively. DBDPE in serum was also significantly and positively associated with the concentrations of TG-Ab and TPO-Ab. Our study found that exposure to DBDPE was associated with changes in thyroid activity in adults exposed to a high concentration of DBDPE, mainly increases of TT4, TT3, TPO-Ab, and TG-Ab. The association between DBDPE exposure and thyroid homeostasis requires further investigation because increasing DBDPE exposure has emerged in recent years.


Assuntos
Bromobenzenos/farmacologia , Exposição Ocupacional , Glândula Tireoide/efeitos dos fármacos , Adulto , China , Feminino , Humanos , Masculino , Tireotropina/sangue , Tiroxina/sangue , Tri-Iodotironina/sangue
8.
Aquat Toxicol ; 216: 105280, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31518776

RESUMO

1,1-Trichloro-2-(p-chlorophenyl)-2-(o-chlorophenyl) ethane (o,p'-DDT) and 1,1-dichloro-2,2-bis (p-chlorophenyl)-ethylene (p,p'-DDE) cause thyroid disruption, but the underlying mechanisms of these disturbances in fish remain unclear. To explore the potential mechanisms of thyroid dysfunction caused by o,p'-DDT and p,p'-DDE, thyroid hormone and gene expression levels in the hypothalamic-pituitary-thyroid (HPT) axis were measured, and the developmental toxicity were recorded in zebrafish larvae. Zebrafish embryos/larvae were exposed to o,p'-DDT (0, 0.28, 2.8, and 28 nM; or 0, 0.1, 1, and 10 µg/L) and p,p'-DDE (0, 1.57, 15.7, and 157 nM; or 0, 0.5, 5, and 50 µg/L) for 7 days. The genes related to thyroid hormone synthesis (crh, tshß, tg, nis and tpo) and thyroid development (nkx2.1 and pax8) were up-regulated in both the o,p'-DDT and p,p'-DDE exposure groups. Zebrafish embryos/larvae exposed to o,p'-DDT showed significantly increased total whole-body T4 and T3 levels, with the expression of ugt1ab and dio3 being significantly down-regulated. However, the p,p'-DDE exposure groups showed significantly lowered whole-body total T4 and T3 levels, which were associated with up-regulation and down-regulation expression of the expression of dio2 and ugt1ab, respectively. Interestingly, the ratio of T3 to T4 was significantly decreased in the o,p'-DDT (28 nM) and p,p'-DDE (157 nM) exposure groups, suggesting an impairment of thyroid function. In addition, reduced survival rates and body lengths and increased malformation rates were recorded after treatment with either o,p'-DDT or p,p'-DDE. In summary, our study indicates that the disruption of thyroid states was different in response to o,p'-DDT and p,p'-DDE exposure in zebrafish larvae.


Assuntos
DDT/toxicidade , Diclorodifenil Dicloroetileno/toxicidade , Embrião não Mamífero/efeitos dos fármacos , Glândula Tireoide/patologia , Peixe-Zebra/embriologia , Animais , Embrião não Mamífero/metabolismo , Regulação da Expressão Gênica no Desenvolvimento/efeitos dos fármacos , Larva/anatomia & histologia , Larva/efeitos dos fármacos , Larva/metabolismo , Glândula Tireoide/efeitos dos fármacos , Glândula Tireoide/metabolismo , Poluentes Químicos da Água/toxicidade , Peixe-Zebra/genética
9.
Chemosphere ; 236: 124834, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31549672

RESUMO

Graphene oxide (GO) has become a topic of increasing concern for its environmental and health risks. However, the potential toxic effects of GO on wildlife remain limited. The present study chose the Xenopus laevis tadpole as a model to assess the thyroid endocrine disruption as well as the lipid metabolic disturbance of GO. Tadpoles at the 51 stage were exposed to GO (0, 0.01, 0.1, and 1 mg/L) for 21 days, when tadpoles were undergoing an extremely complicated phase of morphological changes and growth. GO treatment showed obvious developmental toxicity, such as shortened snout-to-vent length (SVL) and hind limb length (HLL), decreased body weight, and delayed developmental stage. Exposure to GO also induced obvious decreases in whole-body triiodothyronine (T3) and thyroxin (T4) concentrations. The mRNA expression of genes related to the hypothalamic-pituitary-thyroid (HPT) axis also changed significantly. Furthermore, we observed significant decline in the fatty acids and triglycerides (TGs) concomitantly with changes in the expression of genes involved in the synthesis and metabolism of lipids in GO exposure groups. In contrast, high-density lipoprotein (HDL) and total bile acid levels increased remarkably, but cholesterol and low-density lipoprotein (LDH) levels showed no obvious changes. Taken together, the results revealed for the first time that GO could induce thyroid endocrine disruption and produce obvious disturbance effect on lipid synthesis and metabolism.


Assuntos
Disruptores Endócrinos/toxicidade , Grafite/toxicidade , Metabolismo dos Lipídeos/efeitos dos fármacos , Xenopus laevis/metabolismo , Animais , Grafite/farmacologia , Larva/efeitos dos fármacos , Metamorfose Biológica/efeitos dos fármacos , Óxidos/farmacologia , Glândula Tireoide/efeitos dos fármacos , Hormônios Tireóideos/metabolismo , Tiroxina/metabolismo , Tri-Iodotironina/metabolismo , Xenopus laevis/crescimento & desenvolvimento
10.
Ecotoxicol Environ Saf ; 185: 109683, 2019 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-31550567

RESUMO

Thiamethoxam has emerged as an environmental contaminant detected in aqueous environments, and its endocrine-disrupting effect at chronic exposure in teleosts remains unknown. In the present study, a docking experiment and an in vivo test were integrated to systematically explore the toxic mechanisms of thiamethoxam in fish. Histological analysis, plasma VTG and hormone level (E2, 11-KT, T3 and T4) determinations, and HPG and HPT gene expression quantification were performed after Chinese rare minnow (Gobiocypris rarus) was exposed to thiamethoxam (0, 0.5, 5, and 50 µg/L) for 90 days. According to the docking study, thiamethoxam had different interactions with ERα, AR and TRα via hydrogen bonding. A decrease in body length and plasma T4 was observed in both genders. The histological damage in liver and delayed gonadal development were observed in both genders at 50 µg/L thiamethoxam treatment. In males, the following HPG axis genes were upregulated: gnrh and cyp19b in the brain; vtg and cyp19a in the liver; and cyp17 and cyp19a in the gonad. In females, erɑ in the liver was significantly upregulated with 0.5 µg/L thiamethoxam treatment, and cyp17 in the gonad was upregulated with all treatment. The suppression of cyp19a, gnrh, cyp11a, and ttr was observed at the concentration of 5 µg/L in the female liver. Taken together, the endocrine system of Chinese rare minnow might be disrupted after chronic exposure to thiamethoxam.


Assuntos
Cyprinidae/metabolismo , Disruptores Endócrinos/toxicidade , Sistema Endócrino/efeitos dos fármacos , Hormônios/metabolismo , Tiametoxam/toxicidade , Transcriptoma/efeitos dos fármacos , Poluentes Químicos da Água/toxicidade , Animais , Cyprinidae/genética , Sistema Endócrino/metabolismo , Feminino , Gônadas/efeitos dos fármacos , Gônadas/metabolismo , Humanos , Sistema Hipotálamo-Hipofisário/efeitos dos fármacos , Sistema Hipotálamo-Hipofisário/metabolismo , Fígado/efeitos dos fármacos , Fígado/metabolismo , Fígado/patologia , Masculino , Simulação de Acoplamento Molecular , Glândula Tireoide/efeitos dos fármacos , Glândula Tireoide/metabolismo , Glândula Tireoide/patologia , Regulação para Cima , Vitelogeninas/metabolismo
11.
Ecotoxicol Environ Saf ; 185: 109690, 2019 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-31563749

RESUMO

Hexabromocyclododecanes (HBCDs) are the third most highly produced brominated flame retardants (BFRs) all over the world. Based on the current research status of HBCDs, zebrafish were exposed to three dietary concentrations of HBCDs (0, 10, 100, 400 ng/g) for 56 days, and followed by clean food for 28 days. In order to investigate the enrichment and purification of HBCDs in zebrafish, HBCD enantiomers in zebrafish were determined using ultra performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS). To investigate the effects of long-term exposure of HBCDs on thyroid dysfunction and oxidative stress in zebrafish, the concentrations of thyroid hormone (T3, T4, FT3 and FT4) and the activities of malondialdehyde (MDA), superoxide dismutase (SOD), catalase (CAT) and reduced glutathione (GSH) were measured. RT-PCR was used to reveal the molecular mechanism of HBCDs' influence on thyroid hormone in zebrafish. The result of UPLC-MS/MS showed that there were three main reasons for the existence of α-HBCD as the major isomer in the organism. HBCDs had significant inhibitory effect on T3 and T4 in liver of adult zebrafish after 56 days' exposure. Compared with the control group, the ratio of T3 and T4was significantly higher in the medium and high concentration group. The content of FT3 and FT4 in the liver tissue of zebrafish increased first and then decreased with the increase of exposure concentration. With the increase of exposure concentration, the content of MDA in zebrafish liver decreased firstly and then increased. The activity of SOD and CAT in zebrafish liver showed the opposite trend with MDA. And the concentration of GSH in liver decreased gradually, which showed a significant dose-effect relationship. HBCDs exposure has an inhibitory effect on thyroid hormone receptor gene (TRß) and adrenocorticotropin-releasing hormone gene (Crh) in zebrafish.


Assuntos
Retardadores de Chama/toxicidade , Hidrocarbonetos Bromados/toxicidade , Glândula Tireoide/efeitos dos fármacos , Hormônios Tireóideos/metabolismo , Peixe-Zebra/metabolismo , Ração Animal , Animais , Cromatografia Líquida , Exposição Dietética/análise , Relação Dose-Resposta a Droga , Retardadores de Chama/metabolismo , Hidrocarbonetos Bromados/metabolismo , Estresse Oxidativo/efeitos dos fármacos , Estereoisomerismo , Espectrometria de Massas em Tandem , Glândula Tireoide/metabolismo
12.
Ecotoxicol Environ Saf ; 184: 109663, 2019 Nov 30.
Artigo em Inglês | MEDLINE | ID: mdl-31539807

RESUMO

Humidifier disinfectants have been widely used in Korea to prevent the growth of microorganisms in humidifier water. However, their use has been banned since 2011 after epidemiological studies reported humidifier disinfectant induced lung injury. In the present study, the developmental effects of exposure to two humidifier disinfectants (Oxy® and Wiselect) and their main component, polyhexamethylene guanidine (PHMG)-phosphate, were investigated in zebrafish embryos/larvae for seven days. The effects on triiodothyronine (T3) and thyroxine (T4) hormones, reactive oxygen species (ROS) generation, antioxidant enzyme activities, and changes in expression of the genes related to the hypothalamus-pituitary-thyroid (HPT) axis and oxidative stress were also investigated. Zebrafish embryos exposed to the highest concentration (amounts recommended for use by the manufacturers) of all tested humidifier disinfectants showed an increase in embryo coagulation, leading to death without hatching. Exposure to Oxy® and Wiselect resulted in significantly decreased body length, increased ROS generation and antioxidant enzyme activities, decreased T4, and up-regulated genes related to the HPT axis (trh, trß, and tpo) and oxidative damage (sod2 and gpx1b). The humidifier disinfectants and PHMG-phosphate could induce oxidative stress and disrupt thyroid hormone systems in zebrafish, leading to developmental retardation when used at sub-lethal concentrations. Potential effects of long-term exposure to humidifier disinfectants and mixture effects of several major components deserve further investigation.


Assuntos
Desinfetantes/toxicidade , Disruptores Endócrinos/toxicidade , Umidificadores/normas , Peixe-Zebra/crescimento & desenvolvimento , Animais , Larva/efeitos dos fármacos , Larva/crescimento & desenvolvimento , República da Coreia , Glândula Tireoide/efeitos dos fármacos , Glândula Tireoide/crescimento & desenvolvimento , Hormônios Tireóideos/metabolismo
13.
Sci Total Environ ; 697: 134140, 2019 Dec 20.
Artigo em Inglês | MEDLINE | ID: mdl-31476497

RESUMO

Organotin compounds are the ubiquitous environmental pollutants due to their wide industrial and agricultural applications and unexpected releasing into the environment, which show characteristic of endocrine disruptors to interfere with the synthesis, receptor binding or action of endogenous-hormones. Organotin pesticides (OTPs) are used in agriculture and may impact endocrine functions on organisms. Thyroid hormones (THs) play fundamental roles in regulating the basal metabolism and energy balance, while thyroid function can be impaired by environmental contaminants. Therefore, it is crucial to clarify the effects and mechanisms of OTPs on hypothalamus-pituitary-thyroid (HPT) axis. In this study, Xenopus laevis tadpoles at stage 51 were exposed to fentin hydroxide and fenbutatin oxide (0.04, 0.20 and 1.00 µg·L-1) for 21 days. It was found that both compounds caused inhibitory effects on metamorphic development of tadpoles (e.g., significant decrease in hindlimb length and retarding development). Triiodothyronine (T3) significantly decreased in tadpoles exposed to 0.20 µg/L and 1.00 µg/L of the two OTPs for 14 days or 21 days. The expressions of TH responsive genes trß, bteb and dio2 were down-regulated, while tshß and slc5a5 were up-regulated. Surface plasmon resonance (SPR) binding assays showed that fentin hydroxide had a moderate affinity to recombinant human thyroid hormone receptor ß but fenbutatin oxide did not have. Result of the SPR assay was highly consistent with the luciferase reporter gene assays that fentin hydroxide suppressed the relative luciferase activity in the presence of T3 while fenbutatin oxide did not, demonstrating fentin hydroxide but not fenbutatin oxide displayed an antagonistic activity against T3-TR complex mediated transcriptional activation. Overall, the findings elucidated the mechanisms induced by OTPs along HPT axis. These results highlighted the adverse influences of organotin pesticides on thyroid hormone- dependent development in vertebrates and the need for more comprehensive investigations of their potential ecological risks.


Assuntos
Disruptores Endócrinos/toxicidade , Metamorfose Biológica/efeitos dos fármacos , Compostos Orgânicos de Estanho/toxicidade , Praguicidas/toxicidade , Glândula Tireoide/efeitos dos fármacos , Animais , Larva , Glândula Tireoide/fisiologia , Hormônios Tireóideos , Poluentes Químicos da Água/toxicidade , Xenopus laevis
15.
Biol Aujourdhui ; 213(1-2): 17-26, 2019.
Artigo em Francês | MEDLINE | ID: mdl-31274099

RESUMO

An increase in the prevalence of many diseases affecting the nervous system in both children and adults has been reported. Some of these diseases are related to endocrine dysfunction, notably of the thyroid axis. Examples in children are attention deficit/hyperactivity disorders and Autism Spectrum Disorders, diagnosed but most often affecting the whole life, and multiple sclerosis or Alzheimer's disease in adults. It is becoming increasingly clear that embryonic exposure to thyroid hormone disruptors can lead to short- and long-term consequences, that often escape conventional neonatal diagnosis. Endocrine disruptors comprise a wide range of molecules, plasticizers, some pesticides, surfactants, flame-retardants, etc., many of which can interfere with thyroid hormone synthesis or their actions. We here report briefly the history of endocrine disruptors, their properties and the consequences on neuronal development of embryonic exposure to some of them.


Assuntos
Comportamento/efeitos dos fármacos , Encéfalo/efeitos dos fármacos , Encéfalo/embriologia , Disruptores Endócrinos/farmacologia , Glândula Tireoide/efeitos dos fármacos , Adulto , Animais , Antitireóideos/farmacologia , Comportamento/fisiologia , Encéfalo/crescimento & desenvolvimento , Criança , Humanos , Glândula Tireoide/fisiologia , Hormônios Tireóideos/farmacologia
16.
Mol Med Rep ; 20(3): 2332-2338, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31322200

RESUMO

Benign thyroid nodules are among the most common endocrine disorders. Recent advances in diagnostic imaging and pathology have significantly contributed to better risk stratification of thyroid nodules. However, current treatment options, beyond surgical approaches are limited. The following placebo-controlled study presents, to the best of our knowledge, the first results of a non-invasive therapy for benign thyroid nodules. The efficacy and safety of a supplement containing spirulina, curcumin and Boswellia in euthyroid patients with benign thyroid nodules, was assessed by a 3 month, double-blind, placebo-controlled study which was completed by 34 patients. Patients with benign (FNAB documented) single thyroid nodules between 2 and 5 cm were evaluated in a prospective placebo-controlled cross-over trial, across 12 weeks (3 visits with six-week intervals). At each visit, the target thyroid nodule was recorded in two dimensions. In addition, plasma levels of thyroid stimulating hormone, free thyroxine and copper were assessed. The mean initial nodule area at V1 was 4.38±3.14 cm2, at V2 3.87±2.79 cm2, and at V3 3.53±2.84 cm2; P<0.04. Administration of the active substances (n=34) was followed by a mean area decrease of 0.611 cm2±0.933 (SD), while placebo administration (n=29) was followed by a mean decrease of 0.178 cm2±0.515 (SD), (P=0.027). The presented findings suggest that the combination of spirulina-curcumin-Βoswellia is effective in reducing the size of benign thyroid nodules. However, additional studies are needed in order to elucidate the exact mechanisms through which the suggested supplement facilitates a decrease in the size of benign thyroid nodules.


Assuntos
Antineoplásicos Fitogênicos/uso terapêutico , Boswellia , Curcumina/uso terapêutico , Spirulina , Nódulo da Glândula Tireoide/tratamento farmacológico , Adulto , Idoso , Antineoplásicos Fitogênicos/química , Boswellia/química , Curcumina/química , Método Duplo-Cego , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Efeito Placebo , Extratos Vegetais/uso terapêutico , Spirulina/química , Glândula Tireoide/efeitos dos fármacos , Glândula Tireoide/patologia , Nódulo da Glândula Tireoide/sangue , Nódulo da Glândula Tireoide/patologia , Tireotropina/sangue , Tiroxina/sangue
17.
Reprod Toxicol ; 88: 56-66, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-31348994

RESUMO

Recently several OECD test guidelines were updated to include thyroid hormone measurements for assessing endocrine disruptor potency, which led to an imperative need to align interpretation of these results by the different stakeholders. We therefore evaluated 124 repro screening studies, which showed in 38% of the studies a statistical significant finding for T4 in at least one treatment group, probably due to disturbances of normal homeostasis causing high variation. Consequently, for a thorough evaluation it is extremely important to take the historical control range into account. In conclusion, the current testing approach is not providing specific information needed to assess endocrine disruption, as too often a statistical significant finding is noted and as down-stream adverse effects are not evaluated. Therefore, major modifications are urgently needed. Instead of extending the in vivo experiments, it should be investigated if in vitro assessments will provide more relevant information on human endocrine disruptor potential.


Assuntos
Guias como Assunto/normas , Organização para a Cooperação e Desenvolvimento Econômico/normas , Hormônios Tireóideos/sangue , Animais , Disruptores Endócrinos/toxicidade , União Europeia , Feminino , Humanos , Masculino , Ratos , Glândula Tireoide/efeitos dos fármacos , Tireotropina/sangue , Tiroxina/sangue , Toxicologia/métodos , Toxicologia/normas , Tri-Iodotironina/sangue , Estados Unidos
18.
Environ Pollut ; 253: 899-908, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31351298

RESUMO

Triphenyl phosphate (TPHP; CAS # 115-86-6), a commonly used plasticizer and flame retardant, has been reported in wild birds and identified as a potential high-risk chemical. We exposed Japanese quail (Coturnix japonica) by in ovo injection, and once hatched, orally each day for 5 days to safflower oil (controls) or TPHP dissolved in vehicle at low (5 ng TPHP/g), mid (50 ng TPHP/g), or high (100 ng TPHP/g) nominal TPHP doses. The low TPHP dose reflected concentrations in wild bird eggs, with mid and high doses 10x and 20x greater to reflect potential increases in environmental TPHP concentrations in the future. Despite no effects on mRNA expression in thyroid-related genes, TPHP exposure enhanced thyroid gland structure in high TPHP males, but in females, suppressed thyroid gland structure and activity (all TPHP females), and circulating free triiodothyronine (high TPHP females only). Consistent with thyroidal changes, and compared to controls, mid and high TPHP chicks experienced significantly reduced resting metabolic rate (≤13%) and growth (≤53%); mid TPHP males and high TPHP females were significantly smaller. The observed thyroidal effects and suppressed growth and metabolic rate of the quail chicks suggest that TPHP may adversely affect the health of wild birds.


Assuntos
Coturnix/fisiologia , Poluentes Ambientais/toxicidade , Organofosfatos/toxicidade , Glândula Tireoide/efeitos dos fármacos , Animais , Metabolismo Basal , Galinhas/metabolismo , Coturnix/crescimento & desenvolvimento , Feminino , Retardadores de Chama/metabolismo , Retardadores de Chama/toxicidade , Masculino , Plastificantes , Codorniz , Glândula Tireoide/metabolismo , Tri-Iodotironina
19.
Chemosphere ; 236: 124251, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31310984

RESUMO

We examined the Pb2+ exposure on tadpoles of Bufo gargarizans from Gosner stage 26-42. Mortality, growth and development, time to metamorphosis, size, and skeletal ossification at metamorphic climax of Bufo gargarizans were examined. Also, histological characteristics of thyroid glands in tadpoles at Gosner stage 33, 38, and 42 as well as transcript levels of thyroid hormone-related genes in the hind-limb, tail, and liver of tadpoles at metamorphic climax were examined. Pb2+ exposure induced mortality in a concentration-dependent manner in Bufo gargarizans larvae. The significant increase in growth and development, percent metamorphosis, size at metamorphic climax, and skeletal ossification were observed at 50 µg Pb2+ L-1; however, exposure to 1000 µg Pb2+ L-1 resulted in the opposite effects in tadpoles. In addition, histological alterations of thyroid gland, such as follicular cell hyperplasia and colloid depletion could be found in 50-1000 µg Pb2+ L-1 treatments. Furthermore, Pb2+ exposure at 1000 µg L-1 resulted in significantly decreased transcript levels of Dio2, TRα and TRß, and increased transcript levels of Dio3. In contrast, 50 µg Pb2+ L-1 significantly upregulated the mRNA levels of Dio2, TRα, and TRß, but it reduced the Dio3 expression. These results suggested that Pb2+ might disrupt TH homeostasis in tadpoles by histological alterations of thyroid gland and disturb the transcript levels of Dio2, Dio3, TRα, and TRß, leading to altered growth and development, as well as percent metamorphosis and skeletal ossification. Further studies are needed to elucidate the underlying mechanisms of low-dose stimulation and high-dose inhibition effects.


Assuntos
Chumbo/efeitos adversos , Metamorfose Biológica/efeitos dos fármacos , Glândula Tireoide/efeitos dos fármacos , Animais , Larva
20.
J Clin Pharm Ther ; 44(5): 742-749, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31183891

RESUMO

WHAT IS KNOWN AND OBJECTIVE: Thyroid autoimmune diseases occur much more frequently in women than men. Unfortunately, no previous study has determined whether sex hormones produce any effect on thyroid antibody titres. The primary study aim was to assess whether exogenous testosterone affects thyroid autoimmunity in men with Hashimoto's thyroiditis and low testosterone levels. METHODS: The study population consisted of 34 euthyroid men with autoimmune thyroiditis and testosterone deficiency. On the basis of patient preference, these patients were either treated with oral testosterone undecanoate (120 mg daily; n = 16) or remained untreated (n = 18). Circulating levels of thyrotropin, free thyroxine, free triiodothyronine, prolactin and total testosterone, as well as serum titres of thyroid peroxidase and thyroglobulin antibodies, were measured at the beginning of the study and 6 months later. The structure parameters of thyroid homeostasis (Jostel's thyrotropin index, SPINA-GT and SPINA-GD) were also calculated. Moreover, semen analyses were performed in eight patients in each group. RESULTS AND DISCUSSION: In testosterone-naïve men, serum hormone levels and antibody titres remained at the similar levels throughout the study. Apart from increasing serum testosterone levels, testosterone undecanoate reduced titres of thyroid peroxidase and thyroglobulin antibodies and increased SPINA-GT. The drug produced a neutral effect on circulating levels of thyrotropin, free thyroid hormones, prolactin and testosterone, Jostel's thyrotropin index, SPINA-GD and semen parameters. Testosterone-induced changes in antibody titres correlated with the effect of treatment on SPINA-GT and with serum testosterone levels. WHAT IS NEW AND CONCLUSION: This study is the first one to have shown that exogenous testosterone may have a protective effect on thyroid autoimmunity in men with Hashimoto's thyroiditis and testosterone deficiency.


Assuntos
Autoanticorpos/uso terapêutico , Autoimunidade/efeitos dos fármacos , Doença de Hashimoto/tratamento farmacológico , Testosterona/sangue , Testosterona/uso terapêutico , Glândula Tireoide/efeitos dos fármacos , Feminino , Doença de Hashimoto/sangue , Humanos , Inibidores de Hidroximetilglutaril-CoA Redutases/uso terapêutico , Iodeto Peroxidase/sangue , Masculino , Pessoa de Meia-Idade , Testosterona/análogos & derivados , Tireoglobulina/sangue , Hormônios Tireóideos/sangue , Tireotropina/sangue
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