Thyroid Hormone Supplementation Restores Cognitive Deficit, Insulin Signaling, and Neuroinflammation in the Hippocampus of a Sporadic Alzheimer’s-like Disease Rat Model

Thyroid hormones play a crucial role in the development of the central nervous system and are considered pivotal to cognitive functions in the adult brain. Recently, thyroid dysfunction has been associated with Alzheimer’s disease. The aim of this study was to assess the neuroprotective effects of t...

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Main Authors: Paulina Sepúlveda, Ana Flavia Fernandes Ferreira, Cristian Sandoval, Giovanna Bergoc, Ana Caroline Rippi Moreno, Maria Tereza Nunes, Andréa da Silva Torrão
Format: Article
Language:English
Published: MDPI AG 2024-10-01
Series:Cells
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Online Access:https://www.mdpi.com/2073-4409/13/21/1793
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author Paulina Sepúlveda
Ana Flavia Fernandes Ferreira
Cristian Sandoval
Giovanna Bergoc
Ana Caroline Rippi Moreno
Maria Tereza Nunes
Andréa da Silva Torrão
author_facet Paulina Sepúlveda
Ana Flavia Fernandes Ferreira
Cristian Sandoval
Giovanna Bergoc
Ana Caroline Rippi Moreno
Maria Tereza Nunes
Andréa da Silva Torrão
author_sort Paulina Sepúlveda
collection DOAJ
description Thyroid hormones play a crucial role in the development of the central nervous system and are considered pivotal to cognitive functions in the adult brain. Recently, thyroid dysfunction has been associated with Alzheimer’s disease. The aim of this study was to assess the neuroprotective effects of triiodothyronine (T3) on insulin signaling, neuroinflammation, apoptosis, and cognitive function in a streptozotocin (STZ)-induced sporadic Alzheimer’s disease-like model. Male Wistar rats underwent stereotaxic surgery for intracerebroventricular injections of streptozotocin (STZ; 2 mg/kg) or vehicle in the lateral ventricles to induce an AD-like model. The animals received a daily dose of 1.5 μg of T3/100 g body weight or the same volume of vehicle for 30 days and were subdivided into four experimental groups: (1) animals receiving citrate treated with saline (Control = CTL); (2) animals receiving citrate treated with T3 (T3); (3) animals receiving STZ treated with saline (STZ); and (4) animals receiving STZ treated with T3 (STZ + T3). The novel object recognition test was used to measure cognitive function. Serum analysis, real-time RT-PCR, immunohistochemistry, and immunoblotting analyses were also carried out. Our results demonstrated that T3 treatment reversed cognitive impairment and increased Akt and GSK3 phosphorylation in the treated group, while also reducing microglial activation (Iba-1) and GFAP expression (reactive astrocytes), along with TNF-α, IL-6, and IL-1β levels in the hippocampus. Additionally, T3 treatment increased levels of the anti-apoptotic protein Bcl-2 and reduced the expression of the pro-apoptotic protein BAX in the hippocampus. Our study demonstrated that T3 could potentially protect neurons in an AD model induced by STZ.
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spelling doaj-art-852eff3955a44a69979bc41516bdf6402025-08-20T02:49:49ZengMDPI AGCells2073-44092024-10-011321179310.3390/cells13211793Thyroid Hormone Supplementation Restores Cognitive Deficit, Insulin Signaling, and Neuroinflammation in the Hippocampus of a Sporadic Alzheimer’s-like Disease Rat ModelPaulina Sepúlveda0Ana Flavia Fernandes Ferreira1Cristian Sandoval2Giovanna Bergoc3Ana Caroline Rippi Moreno4Maria Tereza Nunes5Andréa da Silva Torrão6Departamento de Ciencias Preclínicas, Facultad de Medicina, Universidad de La Frontera, Temuco 4811230, ChileDepartamento de Fisiologia e Biofísica, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo 05508-000, BrazilEscuela de Tecnología Médica, Facultad de Salud, Universidad Santo Tomás, Los Carreras 753, Osorno 5310431, ChileDepartamento de Fisiologia e Biofísica, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo 05508-000, BrazilDepartamento de Fisiologia e Biofísica, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo 05508-000, BrazilDepartamento de Fisiologia e Biofísica, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo 05508-000, BrazilDepartamento de Fisiologia e Biofísica, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo 05508-000, BrazilThyroid hormones play a crucial role in the development of the central nervous system and are considered pivotal to cognitive functions in the adult brain. Recently, thyroid dysfunction has been associated with Alzheimer’s disease. The aim of this study was to assess the neuroprotective effects of triiodothyronine (T3) on insulin signaling, neuroinflammation, apoptosis, and cognitive function in a streptozotocin (STZ)-induced sporadic Alzheimer’s disease-like model. Male Wistar rats underwent stereotaxic surgery for intracerebroventricular injections of streptozotocin (STZ; 2 mg/kg) or vehicle in the lateral ventricles to induce an AD-like model. The animals received a daily dose of 1.5 μg of T3/100 g body weight or the same volume of vehicle for 30 days and were subdivided into four experimental groups: (1) animals receiving citrate treated with saline (Control = CTL); (2) animals receiving citrate treated with T3 (T3); (3) animals receiving STZ treated with saline (STZ); and (4) animals receiving STZ treated with T3 (STZ + T3). The novel object recognition test was used to measure cognitive function. Serum analysis, real-time RT-PCR, immunohistochemistry, and immunoblotting analyses were also carried out. Our results demonstrated that T3 treatment reversed cognitive impairment and increased Akt and GSK3 phosphorylation in the treated group, while also reducing microglial activation (Iba-1) and GFAP expression (reactive astrocytes), along with TNF-α, IL-6, and IL-1β levels in the hippocampus. Additionally, T3 treatment increased levels of the anti-apoptotic protein Bcl-2 and reduced the expression of the pro-apoptotic protein BAX in the hippocampus. Our study demonstrated that T3 could potentially protect neurons in an AD model induced by STZ.https://www.mdpi.com/2073-4409/13/21/1793Alzheimer’s diseaseinsulin signalingneurodegenerationtriiodothyroninestreptozotocin
spellingShingle Paulina Sepúlveda
Ana Flavia Fernandes Ferreira
Cristian Sandoval
Giovanna Bergoc
Ana Caroline Rippi Moreno
Maria Tereza Nunes
Andréa da Silva Torrão
Thyroid Hormone Supplementation Restores Cognitive Deficit, Insulin Signaling, and Neuroinflammation in the Hippocampus of a Sporadic Alzheimer’s-like Disease Rat Model
Cells
Alzheimer’s disease
insulin signaling
neurodegeneration
triiodothyronine
streptozotocin
title Thyroid Hormone Supplementation Restores Cognitive Deficit, Insulin Signaling, and Neuroinflammation in the Hippocampus of a Sporadic Alzheimer’s-like Disease Rat Model
title_full Thyroid Hormone Supplementation Restores Cognitive Deficit, Insulin Signaling, and Neuroinflammation in the Hippocampus of a Sporadic Alzheimer’s-like Disease Rat Model
title_fullStr Thyroid Hormone Supplementation Restores Cognitive Deficit, Insulin Signaling, and Neuroinflammation in the Hippocampus of a Sporadic Alzheimer’s-like Disease Rat Model
title_full_unstemmed Thyroid Hormone Supplementation Restores Cognitive Deficit, Insulin Signaling, and Neuroinflammation in the Hippocampus of a Sporadic Alzheimer’s-like Disease Rat Model
title_short Thyroid Hormone Supplementation Restores Cognitive Deficit, Insulin Signaling, and Neuroinflammation in the Hippocampus of a Sporadic Alzheimer’s-like Disease Rat Model
title_sort thyroid hormone supplementation restores cognitive deficit insulin signaling and neuroinflammation in the hippocampus of a sporadic alzheimer s like disease rat model
topic Alzheimer’s disease
insulin signaling
neurodegeneration
triiodothyronine
streptozotocin
url https://www.mdpi.com/2073-4409/13/21/1793
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