Experimentally-induced maternal hypothyroidism alters enzyme activities and the sensorimotor cortex of the offspring rats.

Abstract

In this study, we used an experimental model of congenital hypothyroidism to show that deficient thyroid hormones (TH) disrupt different neurochemical, morphological and functional aspects in the cerebral cortex of 15-day-old offspring. Our results showing decreased glutamine synthetase (GS) activity and Ca2+ overload in the cerebral cortex of hypothyroid pups suggest misregulated glutamate metabolism associated with developmentally induced TH deficiency. The 14C-MeAIB accumulation indicates upregulated System A activity and glutamine uptake by neurons. Energy metabolism in hypothyroid cortical slices was preserved, as demonstrated by unaltered glucose metabolism. We also found upregulated acetylcholinesterase activity, depleting acetylcholine from the synaptic cleft, pointing to disrupted cholinergic system. Increased reactive oxygen species (ROS) generation, lipid peroxidation, glutathione (GSH) depletion, which were associated with glutathione peroxidase, superoxide dismutase and gamma-glutamyltransferase downregulation suggest redox imbalance. Disrupted astrocyte cytoskeleton was evidenced by downregulated and hyperphosphorylated glial fibrillary acidic protein (GFAP). Morphological and structural characterization of the sensorimotor cerebral cortex (SCC) showed unaltered thickness of the SCC. However, decreased size of neurons on the layers II & III and IV in the right SCC and increased NeuN positive neurons in specific SCC layers, suggest that they are differently affected by the low TH levels during neurodevelopment. Hypothyroid pups presented increased number of foot-faults in the gridwalk test indicating affected motor functions. Taken together, our results show that congenital hypothyroidism disrupts glutamatergic and cholinergic neurotransmission, Ca2+ equilibrium, redox balance, cytoskeleton integrity, morphological and functional aspects in the cerebral cortex of young rats.

• Authors: Juliana Tonietto Domingues, Carolinne Sayury Wajima, Patricia Acordi Cesconetto, Eduardo Benedetti Parisotto, Elisa Winkelmann-Duarte, Karin Dos Santos, Najla Saleh, Fabíola Branco Filippin-Monteiro, Guilherme Razzera, Fátima Regina Mena Barreto Silva, Regina Pessoa-Pureur, Ariane Zamoner
• Journal: Molecular and cellular endocrinology (Mol Cell Endocrinol) Vol. 478 Pg. 62-76 (12 15 2018) ISSN: 1872-8057 [Electronic] Ireland
• PMID: 30031104 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: Copyright © 2018. Published by Elsevier B.V.

Chemical References

• Antigens, Nuclear
• Glial Fibrillary Acidic Protein
• Nerve Tissue Proteins
• Rbfox3 protein, rat
• Receptors, Cytoplasmic and Nuclear
• Thyroid Hormones
• Glutamic Acid
• Propylthiouracil
• L-Lactate Dehydrogenase
• Acetylcholinesterase
• Glutamate-Ammonia Ligase
• Glucose

Topics

• Acetylcholinesterase (metabolism)
• Animals
• Animals, Newborn
• Antigens, Nuclear (metabolism)
• Behavior, Animal
• Biological Transport
• Body Composition
• Cells, Cultured
• Cerebral Cortex (enzymology)
• Female
• Glial Fibrillary Acidic Protein (metabolism)
• Glucose (metabolism)
• Glutamate-Ammonia Ligase (metabolism)
• Glutamic Acid (metabolism)
• Hypothyroidism (blood, chemically induced, physiopathology)
• L-Lactate Dehydrogenase (metabolism)
• Molecular Docking Simulation
• Motor Activity
• Nerve Tissue Proteins (metabolism)
• Oxidation-Reduction
• Phosphorylation
• Propylthiouracil
• Rats, Wistar
• Receptors, Cytoplasmic and Nuclear (metabolism)
• Sensorimotor Cortex (enzymology)
• Thyroid Gland (metabolism)
• Thyroid Hormones (blood)