Efeito das concentrações suprafisiológicas de hormônios esteroides ovarianos e do estresse crônico sobre parâmetros biométricos, neuroendócrinos e encefálicos de ratas adultas
Data
2024-05-09
Autores
Gonçalves, Bianca Santos Martins 
Orientadores
Le Sueur-Maluf, Luciana
Tipo
Tese de doutorado
Título da Revista
ISSN da Revista
Título de Volume
Resumo
Estima-se que anualmente 7 a 10% dos casais em idade reprodutiva recorram a serviços especializados no tratamento de distúrbios da fertilidade. Enquanto o impacto do estresse no sucesso dos Tratamentos de Reprodução Humana Assistida (TRHA) tem sido extensamente estudado, a ação de concentrações suprafisiológicas de hormônios esteroides ovarianos (situação comumente vivenciada por mulheres em tratamento) na modulação da resposta de estresse e sobre parâmetros biométricos permanecem a ser elucidados. A fim de mimetizar em roedores o contexto dos TRHA, submetemos ratas Wistar adultas ao protocolo de Estresse Crônico Brando Imprevisível (ECBI) por quatro semanas. Durante este período foram aplicados três ciclos de superovulação (150 UI/Kg i.p. de gonadotrofina coriônica equina, seguida de 75 UI/Kg i.p. de gonadotrofina coriônica humana, após 48 horas). As ratas foram distribuídas em 4 grupos: a) Salina/Sem Estresse (Sal/SE); b) Salina/ECBI (Sal/ECBI); c) Repetidas Superovulações/Sem Estresse (RS/SE); e d) Repetidas Superovulações/ ECBI (RS/ECBI). Foram avaliados o padrão de consumo alimentar, a concentração plasmática de hormônio adrenocorticotrófico (ACTH), a massa dos ovários, glândulas adrenais, e depósitos de gorduras viscerais, além da coleta dos encéfalos. As áreas cerebrais recrutadas na resposta de estresse sob a influência hormonal foram avaliadas através da imunomarcação para proteína ΔFosB, marcador de atividade neuronal frente a estímulos crônicos, para investigação dos substratos neurais envolvidos nas alterações comportamentais observadas anteriormente por nosso grupo de pesquisa. As fêmeas do grupo Sal/ECBI apresentaram diminuição significativa na ingestão de alimentos, no ganho de massa corporal e adiposidade visceral, além de redução nos níveis de ACTH. As ratas do grupo RS/SE mostraram aumento significativo na ingestão de alimentos, ganho de massa corporal, adiposidade visceral e massa dos ovários, além de redução nos níveis de ACTH e diminuição da massa e áreas total e cortical das adrenais. Já as ratas do grupo RS/ECBI apresentaram somente aumento da massa dos ovários, redução nos níveis de ACTH e diminuição da massa e áreas total e cortical das adrenais. Nossos resultados sugerem que o recrutamento de áreas encefálicas como o hipotálamo dorsomedial (DMH) e o septo lateral (LS) estão relacionados às mudanças na ingestão alimentar e adiposidade visceral. O grupo Sal/ECBI mostrou recrutamento do núcleo paraventricular do hipotálamo (PVH), amígdala central (CeA) e do DMH, áreas relacionadas à ativação do eixo hipotálamo-hipófise-adrenal (HHA), além de recrutamento do LS e DMH, também envolvidos no comportamento do tipo depressivo. No grupo RS/SE houve recrutamento do LS, núcleo anterior do hipotálamo (AHN) e córtex infralímbico, áreas envolvidas no comportamento do tipo ansioso, observado anteriormente neste grupo, enquanto as ratas expostas a ambos os protocolos (grupo RS/ECBI) apresentaram hipoativação do AHN e do subnúcleo dorsal do LS, sugerindo supressão do comportamento do tipo ansioso, além de ativação do subnúcleo ventral do LS, relacionado ao comportamento adaptativo / resiliência, observados previamente neste grupo. Em conclusão, nossos achados destacam a complexa interação entre os eixos HHA e HHG (hipotálamo-hipófise-gonadal) e indicam que tanto o estresse crônico quanto as repetidas superovulações afetam significativamente parâmetros biométricos e neuroendócrinos em ratas, com importantes implicações comportamentais.
It is estimated that annually 7 to 10% of couples of reproductive age use specialized services for the treatment of fertility disorders. While the impact of stress on the success of Assisted Reproduction Treatments (ART) has been extensively studied, the action of supraphysiological concentrations of ovarian steroid hormones (a situation commonly experienced by women undergoing treatment) in modulating the stress response and on biometric parameters remains to be elucidated. In order to mimic the ART context in rodents, we subjected adult Wistar rats to the Unpredictable Chronic Mild Stress (UCMS) protocol for four weeks. During this period, three cycles of superovulation were applied (150 IU/Kg i.p. of equine chorionic gonadotropin, followed by 75 IU/Kg i.p. of human chorionic gonadotropin, after 48 hours). The rats were divided into 4 groups: a) Saline/No Stress (Sal/NS); b) Saline/ECBI (Sal/UCMS); c) Repeated Superovulations/No Stress (RS/NS); and d) Repeated Superovulations/UCMS (RS/UCMS). The pattern of food consumption, the plasma concentration of adrenocorticotropic hormone (ACTH), the mass of the ovaries, adrenal glands, and visceral fat deposits were evaluated, in addition to collecting the brains. The brain areas recruited in the stress response under hormonal influence were evaluated through immunostaining for ΔFosB protein, a marker of neuronal activity in the face of chronic stimuli, to investigate the neural substrates involved in the behavioral changes previously observed by our research group. Females in the Sal/ECBI group showed a significant decrease in food intake, body mass gain and visceral adiposity, in addition to a reduction in ACTH levels. The rats in the RS/NS group showed a significant increase in food intake, gain in body mass, visceral adiposity and ovarian mass, in addition to a reduction in ACTH levels and a decrease in the mass and total and cortical areas of the adrenal glands. The rats in the RS/UCMS group only showed an increase in ovarian mass, a reduction in ACTH levels and a decrease in the mass and total and cortical areas of the adrenal glands. Our results suggest that the recruitment of brain areas such as the dorsomedial hypothalamus (DMH) and the lateral septum (LS) are related to changes in food intake and visceral adiposity. The Sal/UCMS group showed recruitment of the paraventricular nucleus of the hypothalamus (PVH), central amygdala (CeA) and the DMH, areas related to the activation of the hypothalamic-pituitary-adrenal axis (HPA), in addition to recruitment of the LS and DMH, also involved in depressive-like behavior. In the RS/SE group, there was recruitment of the LS, anterior nucleus of the hypothalamus (AHN) and infralimbic cortex, areas involved in anxiety-like behavior, previously observed in this group, while rats exposed to both protocols (RS/UCMS group) showed hypoactivation of the AHN and the dorsal subnucleus of the LS, suggesting suppression of anxiety-like behavior, in addition to activation of the ventral subnucleus of the LS, related to adaptive behavior/resilience, previously observed in this group. In conclusion, our findings highlight the complex interaction between the HHA and HHG (hypothalamic-pituitary-gonadal) axes and indicate that both chronic stress and repeated superovulation significantly affect biometric and neuroendocrine parameters in female rats, with important behavioral implications.
It is estimated that annually 7 to 10% of couples of reproductive age use specialized services for the treatment of fertility disorders. While the impact of stress on the success of Assisted Reproduction Treatments (ART) has been extensively studied, the action of supraphysiological concentrations of ovarian steroid hormones (a situation commonly experienced by women undergoing treatment) in modulating the stress response and on biometric parameters remains to be elucidated. In order to mimic the ART context in rodents, we subjected adult Wistar rats to the Unpredictable Chronic Mild Stress (UCMS) protocol for four weeks. During this period, three cycles of superovulation were applied (150 IU/Kg i.p. of equine chorionic gonadotropin, followed by 75 IU/Kg i.p. of human chorionic gonadotropin, after 48 hours). The rats were divided into 4 groups: a) Saline/No Stress (Sal/NS); b) Saline/ECBI (Sal/UCMS); c) Repeated Superovulations/No Stress (RS/NS); and d) Repeated Superovulations/UCMS (RS/UCMS). The pattern of food consumption, the plasma concentration of adrenocorticotropic hormone (ACTH), the mass of the ovaries, adrenal glands, and visceral fat deposits were evaluated, in addition to collecting the brains. The brain areas recruited in the stress response under hormonal influence were evaluated through immunostaining for ΔFosB protein, a marker of neuronal activity in the face of chronic stimuli, to investigate the neural substrates involved in the behavioral changes previously observed by our research group. Females in the Sal/ECBI group showed a significant decrease in food intake, body mass gain and visceral adiposity, in addition to a reduction in ACTH levels. The rats in the RS/NS group showed a significant increase in food intake, gain in body mass, visceral adiposity and ovarian mass, in addition to a reduction in ACTH levels and a decrease in the mass and total and cortical areas of the adrenal glands. The rats in the RS/UCMS group only showed an increase in ovarian mass, a reduction in ACTH levels and a decrease in the mass and total and cortical areas of the adrenal glands. Our results suggest that the recruitment of brain areas such as the dorsomedial hypothalamus (DMH) and the lateral septum (LS) are related to changes in food intake and visceral adiposity. The Sal/UCMS group showed recruitment of the paraventricular nucleus of the hypothalamus (PVH), central amygdala (CeA) and the DMH, areas related to the activation of the hypothalamic-pituitary-adrenal axis (HPA), in addition to recruitment of the LS and DMH, also involved in depressive-like behavior. In the RS/SE group, there was recruitment of the LS, anterior nucleus of the hypothalamus (AHN) and infralimbic cortex, areas involved in anxiety-like behavior, previously observed in this group, while rats exposed to both protocols (RS/UCMS group) showed hypoactivation of the AHN and the dorsal subnucleus of the LS, suggesting suppression of anxiety-like behavior, in addition to activation of the ventral subnucleus of the LS, related to adaptive behavior/resilience, previously observed in this group. In conclusion, our findings highlight the complex interaction between the HHA and HHG (hypothalamic-pituitary-gonadal) axes and indicate that both chronic stress and repeated superovulation significantly affect biometric and neuroendocrine parameters in female rats, with important behavioral implications.
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Citação
GONÇALVES, Bianca Santos Martins. Efeito das concentrações suprafisiológicas de hormônios esteroides ovarianos e do estresse crônico sobre parâmetros biométricos, neuroendócrinos e encefálicos de ratas adultas. 2024. 106 f. Tese (Doutorado Interdisciplinar em Ciências da Saúde) - Universidade Federal de São Paulo, Instituto de Saúde e Sociedade, Santos, 2024.