Résumé
Abstract Understanding the relation between the environmental stress factors and the hypothalamus-pituitary-thyroid (HPT) axis efficiency can reduce the susceptibility to thyroid diseases. In our study, thyroid dysfunction was induced in female rats by administration of 40 mg Na F/kg.bd.wt/day for a month. Co-administration of the water extract of Arca noae (300 mg/kg. bw) was tested as a treatment for Na F induced thyroid dysfunction. A group of rats injected Arca noae extract only (300 mg/kg.bd.wt) was performed to observe the impact of the extract on the (HPT) axis in addition to the normal control group. Results showed that there was a significant decrease in serum triglycerides, total protein and albumin levels in the fluoride supplemented group in addition to abnormal levels of TSH, (T4) and (T3) compared to the control group. In the treated group there was an improvement in the proteins level and lipid profile but pseudo-corrected serum (T4) and (T3) levels were observed in addition to a continuous increase in TSH level. Histological findings confirmed the harmful effect of fluoride on both the non treated and the treated groups. Consequently, fluoride supplementation must be considered as a harmful stress that may affect permanently the HPT axis.
Resumo Compreender a relação entre os fatores de estresse ambiental e o eixo hipotálamo-hipófise-tireoide (HPT) pode reduzir a suscetibilidade a doenças da tireoide. Em nosso estudo, a disfunção tireoidiana foi induzida em ratos fêmeas pela administração de 40 mg Na F/kg.bw/dia durante um mês. A administração concomitante do extrato aquoso de Arca noae (300 mg/kg.Pc) foi testada como tratamento para a disfunção tireoidiana induzida por Na F. Um grupo de ratos injetados apenas com extrato de Arca noae (300 mg/kg. Pc) foi pré-formado com o intuito de observar o impacto do extrato no eixo (HPT), além do grupo controle normal. Os resultados mostraram que houve uma diminuição significativa nos níveis séricos de triglicerídeos, proteína total e albumina no grupo suplementado com fluoreto, além de níveis anormais de TSH, (T4) e (T3) em comparação ao grupo controle. No grupo tratado, houve uma melhora no nível de proteínas e perfil lipídico. Os níveis séricos pseudocorrigidos (T4) e (T3) foram observados, além de um aumento contínuo no nível de TSH. Os achados histológicos confirmaram o efeito prejudicial do flúor nos grupos não tratado e tratado. Consequentemente, a suplementação de flúor é considerada um estresse prejudicial que pode afetar permanentemente o eixo HPT.
Sujets)
Animaux , Femelle , Rats , Maladies de la thyroïde , Thyréostimuline , Thyroxine , Organismes aquatiquesRésumé
Abstract Understanding the relation between the environmental stress factors and the hypothalamus-pituitary-thyroid (HPT) axis efficiency can reduce the susceptibility to thyroid diseases. In our study, thyroid dysfunction was induced in female rats by administration of 40 mg Na F/kg.bd.wt/day for a month. Co-administration of the water extract of Arca noae (300 mg/kg. bw) was tested as a treatment for Na F induced thyroid dysfunction. A group of rats injected Arca noae extract only (300 mg/kg.bd.wt) was performed to observe the impact of the extract on the (HPT) axis in addition to the normal control group. Results showed that there was a significant decrease in serum triglycerides, total protein and albumin levels in the fluoride supplemented group in addition to abnormal levels of TSH, (T4) and (T3) compared to the control group. In the treated group there was an improvement in the proteins level and lipid profile but pseudo-corrected serum (T4) and (T3) levels were observed in addition to a continuous increase in TSH level. Histological findings confirmed the harmful effect of fluoride on both the non treated and the treated groups. Consequently, fluoride supplementation must be considered as a harmful stress that may affect permanently the HPT axis.
Resumo Compreender a relação entre os fatores de estresse ambiental e o eixo hipotálamo-hipófise-tireoide (HPT) pode reduzir a suscetibilidade a doenças da tireoide. Em nosso estudo, a disfunção tireoidiana foi induzida em ratos fêmeas pela administração de 40 mg Na F/kg.bw/dia durante um mês. A administração concomitante do extrato aquoso de Arca noae (300 mg/kg.Pc) foi testada como tratamento para a disfunção tireoidiana induzida por Na F. Um grupo de ratos injetados apenas com extrato de Arca noae (300 mg/kg. Pc) foi pré-formado com o intuito de observar o impacto do extrato no eixo (HPT), além do grupo controle normal. Os resultados mostraram que houve uma diminuição significativa nos níveis séricos de triglicerídeos, proteína total e albumina no grupo suplementado com fluoreto, além de níveis anormais de TSH, (T4) e (T3) em comparação ao grupo controle. No grupo tratado, houve uma melhora no nível de proteínas e perfil lipídico. Os níveis séricos pseudocorrigidos (T4) e (T3) foram observados, além de um aumento contínuo no nível de TSH. Os achados histológicos confirmaram o efeito prejudicial do flúor nos grupos não tratado e tratado. Consequentemente, a suplementação de flúor é considerada um estresse prejudicial que pode afetar permanentemente o eixo HPT.
Résumé
Objective To study the function and diurnal variation of hypothalamic-pituitary-adrenal (HPA) axis and hypothalamic-pituitary-thyroid(HPT) axis,and the relationship with clinical characteristics of di-urnal rhythm in depressed patients. Methods Forty-nine depressed patients met diagnostic DSM-Ⅳ criteria and thirty-eight normal controls were collected. The plasma levels of cortisol (CORT), adrenocorticotropic hormone (ACTH), T3, T4, thyroid-stimulating hormone (TSH) at 7 am and 7 pm were measured by radioimmunoassay, then the results concemed were compared among the depressed groups with and without diurnal variation and control group by multivariate analysis of variance. Results The plasma level of morning CORT, morning and evening TSH ((365.94±120.78) nmol/L; (6.24±2.47)μIU/ml; (6.68±2.42)μIU/ml; respectively) were respective-ly higher than those of control group((284.91±83.39) nmol/L; (3.82±1.75)μIU/ml;(4.01±1.69)μIU/ ml, P<0.05). The plasma levels of morning and evening T4 were significantly lower than those of control group(P <0.05). The CORT morning-evening difference variable distinguished between depressed and control group (P< 0.001),but no significant differences could be found between the depressed groups with and without diurnal varia-tion. There were no significant differences in the CORT, T3, T4, TSH morning-evening difference variable between various clinical subtypes of depressed patient (unipolar/bipolar; psychotic/nonpsychotic). Conclusion Abnormal CORT morning-evening difference variable was observed in the depressed patients compared with normal controls,and may be used as a special trait mark of depressed group.