MELATONIN PREVENTS APOPTOSIS IN BRAINS OF NEONATES INDUCED BY MATERNAL HYPOTHYROIDISM
AbstractBackground: Loss of motor neurons may underlie some of the deficits in cognitive functions associated with maternal hypothyroidism during fetal and neonatal period. This experiment was performed to highlight the significance of melatonin intake by the mother in hypothyroid state during gestation and lactation to preserve the integrity of motor neurons in the newborns. Methods: Twelve female Wistar rats were divided equally into four groups, including control (A), hypothyroid (B), melatonin treated hypothyroid (C) and only melatonin treated (D) groups and allowed to conceive. For inducing hypothyroidism, Propylthiouracyl (PTU) was administered in a dose of 15mg/kg/day orally mixed with chow a week before mating and throughout the period of gestation and weaning up till 22nd day after delivery. Melatonin was given in a dose of 10mg/kg/100ml of drinking water. After delivery, 10 neonatal rats from each group were sacrificed on 22nd day of life and blood samples were immediately collected for evaluating serum levels of T3, T4 and TSH. The freshly extracted brains were sliced into two equal parts from the midline. One half was instantly immersed in ice cold phosphate buffered saline and homogenized for extraction of RNA to determine the genetic expressions of caspases 3, 8 and 9. Other half of the brain was instantly immersed in 10% formalin for 2 weeks. After processing of the brain tissue, 5 μm thick sections were sliced and transferred to albumin coated glass slides. They were later stained by Nissl staining technique, visualized and photographed under a research microscope for signs of apoptosis. The mRNA and protein levels of caspase-3, 8, and 9 were analyzed using a real-time RT-PCR. Results: Serum enzyme analysis showed that the pups of dams taking PTU were severely hypothyroid and melatonin treated rats showed significant restoration of serum thyroid hormone levels. Features of apoptosis and disturbed migration of cells was seen in B group as compared to C group and mRNA levels of caspase-3 and 9 were increased significantly in B group. Conclusion: Melatonin helps to maintain neuronal function in hypothyroid newborn rats by inhibiting apoptosis and improving survival.Keywords: Hypothyroidism; melatonin; propylthiouracil; hippocampus; pyramidal neurons; Caspases
Miell JP, Taylor AM, Zini H, Maheshwari HG, Ross RJ, Valcavi R. Valcavi Effects of hypothyroidism and hyperthyroidism on insulin-like growth factors (IGFs) and growth hormone- and IGF-binding proteins. J Clin Endocrinol Metab 1993;76(4):950–5.
Prezioso G, Giannini C, Chiarelli F. Effect of Thyroid Hormones on Neurons and Neurodevelopment. Horm Res Paediatr 2018;90(2):73–81.
Chen C, Zhou Z, Zhong M, Zhang Y, Li M, Zhang L, et al. Thyroid hormone promotes neuronal differentiation of embryonic neural stem cells by inhibiting STAT3 signaling through TRα1. Stem Cells Dev 2012;21(14):2667–81.
Bernal J. Thyroid Hormones in Brain Development and Function. In: Feingold KR, Anawalt B, Boyce A, editors. Endotext [Internet]. South Dartmouth (MA): MDText.com, Inc.; 2000-. [cited 2019 July 14]. Available from: https://www.ncbi.nlm.nih.gov/books/NBK285549
Amaral DG, Witter MP. The three-dimensional organization of the hippocampal formation: a review of anatomical data. Neuroscience 1983;31(3):571–91.
Cherubini E, Miles R. The CA3 region of the hippocampus: how is it? What is it for? How does it do it? Front Cell Neurosci 2015;9:19.
Bárez-López S, Guadaño-Ferraz A. Thyroid Hormone Availability and Action during Brain Development in Rodents. Front Cell Neurosci 2017;11:240.
Nucera C, Muzzi P, Tiveron C, Farsetti A, La Regina F, Foglio B, et al. Maternal thyroid hormones are transcriptionally active during embryo-foetal development: results from a novel transgenic mouse model. J Cell Mol Med 2010;14(10):2417–35.
Chatonnet F, Picou F, Fauquier T, Flamant F. Thyroid hormone action in cerebellum and cerebral cortex development. J Thyroid Res 2011;2011:145762.
Cheng SY, Leonard JL, Davis PJ. Molecular aspects of thyroid hormone actions. Endocr Rev 2010;31(2):139–70.
Mendoza A, Hollenberg AN. New insights into thyroid hormone action. Pharmacol Ther 2017;173:135–45.
Lazarus J. Thyroid Regulation and Dysfunction in the Pregnant Patient. In: Feingold KR, Anawalt B, Boyce A, Chrousos G, Dungan K, Grossman A, et al., editors. Endotext [Internet]. South Dartmouth (MA): MDText.com, Inc.; 2000 [cited 2019 Jul 14]. Available from: http://www.ncbi.nlm.nih.gov/books/NBK279059/
Ryu JR, Hong CJ, Kim JY, Kim EK, Sun W, Yu SW. Control of adult neurogenesis by programmed cell death in the mammalian brain. Mol Brain 2016;9:43.
Algeciras-Schimnich A, Barnhart BC, Peter ME. Apoptosis Dependent and Independent Functions of Caspases. In: Madame Curie Bioscience Database [Internet]. Austin (TX): Landes Bioscience; 2000-2013. [cited 2019 July 14]. Available from: https://www.ncbi.nlm.nih.gov/books/NBK6198
Alzerjawi JM. Effect of propylthiouracil-induced hypothyroidism on reproductive efficiency of adult male rats. Bas J Vet Res 2013;12(2):113–21.
Hidayat M, Shoro AA, Naqvi A. Protective role of melatonin and insulin on streptozotocin induced nephrotoxicity in albino rats. Pak J Med Health Sci 2012;6(3):669–74.
Suvarna KS, Layton C, Bancroft JD. Bancroft's Theory and Practice of Histological Techniques, 7th edition, Churchill Livingstone Elsevier Health Science; 2018.
Moon SH, Lee BJ, Kim SJ, Kim HC. Relationship between thyroid stimulating hormone and night shift work. Ann Occup Environ Med 2016;28:53.
Dugbartey AT. Neurocognitive Aspects of Hypothyroidism. Arch Intern Med 1998;158(13):1413–8.
Berbel P, Navarro D, Román GC. An evo-devo approach to thyroid hormones in cerebral and cerebellar cortical development: etiological implications for autism. Front Endocrinol (Lausanne) 2014;5:146.
Stepien BK, Huttner WB. Transport, Metabolism, and Function of Thyroid Hormones in the Developing Mammalian Brain. Front Endocrinol (Lausanne) 2019;10:209.
Zoeller RT. Transplacental thyroxine and fetal brain development. J Clin Invest 2003;111(7):954–7.
Parrish AB, Freel CD, Kornbluth S. Cellular mechanisms controlling caspase activation and function. Cold Spring Harb Perspect Biol 2013;5(6):a008672.
Shukitt-Hale B, Kadar T, Marlowe BE, Stillman MJ, Galli RL, Levy A, et al. Morphological alterations in hippocampus following hypobaric hypoxia. Hum Exp Toxicol 1996;15(4):312–9.
Srinivasan V, Spence DW, Pandi-Perumal SR, Brown GM, Cardinali DP. Melatonin in mitochondrial dysfunction and related disorders. Int J Alzheimers Dis 2011;2011:326320.
Moriya T, Horie N, Mitome M, Shinohara K. Melatonin influences the proliferative and differentiative activity of neural stem cells. J Pineal Res 2007;42(4):411–8.
Reiter RJ, Tan DX, Rosales-Corral, Galano A, Zhou XJ, Xu B. Mitochondria: Central Organelles for Melatonin's Antioxidant and Anti-Aging Actions. Molecules 2018;23(2):E509.
Tan DX, Manchester LC, Qin L, Reiter RJ. Melatonin: A Mitochondrial Targeting Molecule Involving Mitochondrial Protection and Dynamics. Int J Mol Sci 2016;17(12):E2124