RESUMO
RESUMEN Introducción: El correcto funcionamiento del eje hipotálamo-hipófisis-tiroides es indispensable para el crecimiento y desarrollo embrionario-fetal, al intervenir en la diferenciación de los tejidos, el desarrollo cerebral y somático, la maduración ósea y la regulación del metabolismo. El paso de las hormonas tiroideas maternas al feto a través de la placenta depende de transportadores transmembrana, enzimas desyodinasas (DIO2 y DIO3) y proteínas transportadoras (TTR). Objetivo: Identificar las zonas de expresión de DIO3 y TTR en la placenta de ratón Mus musculus E10.5, E12.5, E14.5. Métodos: La estructura placentaria y expresión de DIO3 y TTR fueron evaluadas con técnicas histoquímicas e inmunofluorescencia. Resultados: Desde E10.5 se encontraron las tres zonas placentarias, laberinto, zona de unión y decidua. En E12.5 se observó la conformación placentaria definitiva. DIO3 y TTR fueron detectadas en los tres estadios, con predominio en la zona del laberinto. Conclusión: DIO3 y TTR se expresan a lo largo del establecimiento y maduración de la placenta de ratón. El biomodelo murino es una herramienta útil para el estudio del transporte placentario de hormonas tiroideas desde la circulación materna a la fetal.
ABSTRACT Introduction: Correct functioning of hypothalamic-pituitary-thyroid axis is essential for embryonic-fetal growth and development, as it is involved in tissue differentiation, brain and somatic development, bone maturation and metabolic regulation. Maternal thyroid hormones passage to the fetus through the placenta depends on transmembrane transporters, deiodinase enzymes (DIO2 and DIO3) and carrier proteins (TTR). Objective: Identify DIO3 and TTR expression within placental layers of Mus musculus E10.5, E12.5 and E14.5. Methods: Placental structure, DIO3 and TTR expression were evaluated using histochemistry and immunofluorescence techniques. Results: We found that the three placental layers, labyrinth zone, junctional zone, and decidua were present since E10.5. At E12.5 placental final conformation was observed. DIO3 and TTR were detected in the three stages with a predominance in the labyrinth. Conclusion: DIO3 and TTR are expressed throughout the establishment and maturation of mouse placenta. Mice are a useful tool for studying how thyroid hormones are transported from maternal t° fetal circulation at the placenta.
RESUMO Introdução: O correto funcionamento do eixo hipotálamo-hipófise-tireoide é essencial para o crescimento e desenvolvimento embrionário-fetal, pois intervém na diferenciação dos tecidos, desenvolvimento cerebral e somático, maturação óssea e regulaçãodo metabolismo. A passagem dos hormônios tireoidianos maternos para o feto através da placenta depende de transportadores transmembranas, enzimas deiodinase (DIO2 e DIO3) e proteínas transportadoras (TTR). Objetivo: Identificar as zonas de expressão de DIO3 e TTR na placenta de rato Mus musculus E10.5, E12.5, E14.5. Métodos: A estrutura placentária e a expressão de DIO3 e TTR foram avaliadas com técnicas histoquímicas e imunofluorescência. Resultados: De E10.5 as três zonas placentárias, labirinto, zona de união e decídua foram encontradas. Em E12.5 a conformação definitiva da placenta foi observada. O DIO3 e o TTR foram detectados nas três fases, com predomínio na área do labirinto. Conclusão: DIO3 e TTR são expressos ao longo do estabelecimento e maturação da placenta de rato O biomodelo murino é uma ferramenta útil para o estudo do transporte placentário dos hormônios tireoidianos da circulação materna para a fetal.
RESUMO
Objective To set up the model of deiodinase ( Dio) 3b-/- zebrafish and to observe the effect of which on embryo development. Methods The zebrafish model of Dio3b-/- was set up by CRISPR-Cas9 gene editing technology, PCR and sequencing was used to confirm the efficiency of deletion. The heart rate of embryos at 48 hours post fertilization was counted. The locomotor activity of 5-7 days post fertilization larve was detected using behavior tracking system. Results The model of Dio3b knockout zebrafish was set up successfully. The heart rate of embryos Dio3b-/- increased ( P＜0. 001) and the locomotor activity of 5-7 days post fertilization larves lacking Dio3b gene increased (P＜0.05) significantly compared with that of wild type control respectively. Conclusion The deletion of zebrafish Dio3b gene results in the phenotype of hyperthyroidism and the model of Dio3b-/- is proper for studying the effect of partial excess thyroid hormone on embryo development.
RESUMO
Objective To explore the effect of endotoxemia on triiodothyronine (T3) and thyroxine (T4),and the level and activity of iodothyronine deiodinase type 1 and type 3 mRNA.Methods Sixteen mice were randomly divided into control group and lipopolysaccharide (LPS) group,with 8 mice in each group.The mouse model of endotoxemia was replicated in the LPS group.In the both groups,blood samples from femoral week were collected to assay T3 and T4 levels,and the livers were sampled to inspect D1 and D3 mRNA levels and activities.Serum T3 and T4 levels were assayed with radioimmunoassay,D1 and D3 mRNA levels in liver were detected with real-time polymerase chain reaction,the activity of D1 and D3 in liver were measured by using ion-exchange chromatography combined with immunoassay.The data were statistically analyzed by SPSS 13.0 software.Results Statistical differences of T3,D1 and D3 mRNA levels and activities between the 2 groups were found (all P ＜0.01),while,there was no statistic difference in the statuses of T4 (P ＞ 0.05).Conclusions It is possible that euthyroid sick syndromes happens in endotoxemia episodes,and the changes of D1 and D3 mRNA levels and activities are the possible influencing factors.
RESUMO
Objective To investigate the expression of type Ⅱ and type Ⅲ iodothyronine deiodinases (D2 and D3 ) of human placenta on pregnant women with different thyroid diseases and different autoimmunity.Methods Pregnant women with different thyroid diseases and autoimmunity were selected into the experiment group,and pregnant women who had no individual or family history of thyroid diseases with normal thyroid function and negative thyroid peroxidase antibody (TPOAb) were selected into the control group.Expression level of iodothyronine deiodinase( D2 and D3 )on placenta was measured by RT-PCR.Results D2 and D3 were both expressed on human placenta.D2 showed significantly higher expression level in hypothyroidism uncontrolled group than that in control group ( 0.916 ± 0.035 vs 0.833 ± 0.029,P ＜ 0.05 ),however,D3 showed a lower expression(0.766 ±0.038 vs 0.848 ±0.052),on placenta and the difference was not significant(P ＞ 0.05 ).In those who had history of hyperthyroidism or hypothyroidism but whose thyroid function become normal by effective treatment,D2 and D3 expression exhibited no difference from that of the control(P ＞ 0.05).In those pregnant women with normal thyroid function and TPOAb-positive,D2 and D3 expression was (0.842 ± 0.032 ) and ( 0.837 ± 0.053 ) respectively and there was also no difference from that of the control( P ＞ 0.05 ).Conclusion D2 and D3 were simultaneously expressed on human placenta.In those pregnant women with hypothyroidism,the level of D2 expression is high and the level of D3 expression is low.Those changes might be important and helpful for the stabilization of thyroid hormone transportation between mother and fetus.
RESUMO
A utilização de esteróides anabolizantes por indivíduos que desejam aumentar sua performance física, ou simplesmente para fins estéticos, tem atingido índices alarmantes nas últimas três décadas. Além dos efeitos desejados, uma infinidade de efeitos colaterais já foi bem descrita na literatura, como vários tipos de câncer, ginecomastia, peliosis hepatis, insuficiência renal, virilização, dentre outros. Sobre a função tireóidea, o efeito mais pronunciado em seres humanos é a diminuição da TBG, com conseqüente diminuição sérica de T3 e T4 totais, dependendo, porém, da susceptibilidade da molécula à aromatização e conseqüente transformação em estrógeno. Em ratos, o tratamento com esteróides anabolizantes altera a metabolização periférica dos hormônios tireóideos e também parece causar importante efeito proliferativo sobre as células tireóideas. Assim, o presente artigo visa rever os dados publicados acerca dos efeitos de doses suprafisiológicas de esteróides anabolizantes sobre a função tireóidea, reforçando o perigo que a utilização indiscriminada dessas drogas pode causar à saúde.
The use of anabolic steroids to increase physical performance and for aesthetic ends has reached alarming indices in the last three decades. Besides the desired actions, several collateral effects have been described in the literature, such as the development of some types of cancer, ginecomasty, peliosis hepatis, renal insufficiency, virilization, amongst others. The most proeminent effect on human thyroid function is the reduction of thyroxine binding globulin (TBG), with consequent reductions of total serum T3 and T4, depending however on the susceptibility of the drug to aromatization and subsequent transformation into estrogen. In rats, anabolic steroids also act in the peripheral metabolism of thyroid hormones and seem to exert an important proliferative effect on thyroid cells. Thus, the aim of the present paper is to review data on the effect of supraphysiological doses of anabolic steroids on thyroid function, showing the danger that indiscriminate use of these drugs can cause to health.
Assuntos
Animais , Humanos , Ratos , Anabolizantes/efeitos adversos , Glândula Tireoide/efeitos dos fármacos , Glândula Tireoide/fisiologia , Tireotropina/fisiologia , Anabolizantes/administração & dosagem , Dopagem Esportivo , Relação Dose-Resposta a Droga , Iodeto Peroxidase/sangue , Testes de Função Tireóidea , Hormônios Tireóideos/fisiologiaRESUMO
Objective To study the activity of type 2 Iodothyronine deiodinase(D2)and the expressions of myelin basic protein(MBP)and synapsinⅠin the brain tissue of young rats fed on a diet with different levels of iodine.Methods Wistar rats were fed on a diet with different doses of KIO_3 for 3 months and then mated randomly.The serum TH and the brain D2 activity were measured in 28 days old pups.The protein expressions of MBP and SynapsinⅠin their brains were determined by immunohistochemistry staining.Results Compared with normal iodine group(NI),the serum TH levels of low iodine group(LI) were lower,while those of iodine excess groups were gradually decreased with their increase of iodine intake,especially in 100-fold high iodine group(100 HI),TT_4 and FT_4 were significantly decreased(P0.05).The immunohistochemistry staining showed weakly positive reactivity of MBP in corpus callosum and stronger of synapsin I in hippocampus CA3 in LI group compared with NI. The similar alterations were also found in all iodine excess groups with their increase of iodine intake.But MBP reactivity was stronger in 100 HI rats than the LI ones.Conclusion Iodine deficiency and iodine excess can cause hypothyroidism in degrees in the young rats,more severe hypothyroid and retarded myelin sheath and synapses can be caused in iodine deficiency compared with iodine excess.
RESUMO
Thyroid function ultimately depends on appropriate iodine supply to the gland. Thyroid hormone deiodination is an intrinsic component of the thyroid hormone homeostasis. Type Ⅰ iodothyronine deiodinase (D1) plays an important role in thyroid hormone metabolism and has close relationship with thyroid function. Based on successfully establishing animal models of iodine deficiency and iodine excess in Babl/c mice (Babl/c mice were randomly divided into five groups: low iodine (LI), normal iodine (NI), five-fold iodine (5HI) , ten-fold iodine (10HI) and fifty-fold iodine (50HI) group. Three months and six months after admistration, they were sacrificed and thyroids were excised), the expression level of D1 mRNA were examined by using real time quantitative PCR method. D1 activity was analyzed by 125I-rT3 as substrate combined with ion-exchange chromatography. The thyroid hormone was measured with radioimmunoassay method. The data revealed that in the case of iodine deficiency, both D1 mRNA expression and D1 activity was greatly increased(compared with NI groups, P
RESUMO
BACKGROUND: Type 1 iodothyronine deiodinase (D1), the product of the hdio1 gene, is involved in thyroid hormone activation by the deiodination of thyroxine (T4) to form 3, 5, 3'-triiodothyronine (T3). Recent studies have identified two thyroid hormone response elements (TREs) in the 5 flanking region of the hdio1 gene. TRE1, proximal to TRE in the hdio1 gene, consists of a direct repeat of thyroid hormone receptor (TR) binding octamers with 10 bp separating the two TR binding sites. The upstream TRE, TRE2, is a classical direct repeat of retinoid X receptor (RXR)/TR binding half-sites with a 4-bp separation. There are few studies clarifying the TR dynamics in the TRE of a specific gene with or without the exposure of activated thyroid hormone. We evaluated TR binding patterns in the proximal and distal TREs of the hdio1 gene before and after T3 stimulation. METHODS: We employed chromatin immunoprecipitation (ChIP) technique to investigate the TR-TRE interaction before and after T3 stimulation in human hepatocellular carcinoma HepG2 cell line.Following cross-linking and sonication of the cells, immunoprecipitation was performed overnight at 4degrees C with TR 1, TR 1 and TR 2 antibodies. We analyzed the binding patterns and amounts of TR 1, TR 1 and TR 2 to TRE1 and TRE2 before and after 12 hours stimulation with 100 nM T3 by using conventional and quantitative real-time polymerase chain reactions (RQ-PCR). Reverse transcriptional PCR (RT-PCR) and Western blot with TR 1, TR 1 and TR 2 antibodies were performed to measure the levels of hdio1 mRNA and TR 1, TR 1 and TR 2 proteins before and after 12 hours exposure to 100 nM T3. RESULTS: In TRE1, TR 1 binding was significantly decreased after 12 hours stimulation with 100nM T3 (3.74-->1.97, delta=-47.3%, p3.01, delta=-71.1%, p 2.93, delta=-76.7%, p 9.84, delta=+7.3%). Total TR bindings in TRE2 were significantly decreased after 12 hours stimulation with 100 nM T3 (32.14 --> 15.78, delta=-50.9%, p<0.05). The TR bindings to TRE1 and TRE2 were not significantly different by the amounts of TR antibodies used during ChIP assays. The levels of hdio1 mRNA were significantly increased, 2.03 times, after 12 hours exposure to 100nM T3 (p<0.001). Western blot showed no significant change of the level of each TR isoform protein before and after 12 hours exposure to 100 nM T3. CONCLUSION: Our results demonstrate the dynamics of TR 1 at proximal TRE (TRE1) and the switching phenomenon of TR isoforms at distal TRE (TRE2) of the hdio1 gene after T3 stimulation. Further investigation, however, is needed to clarify the mechanisms of these observations.