Effect of selenium on impaired learning and memory performance by 6-n-propyl-2-thiouracil in rats

Year 2022, Volume: 15 Issue: 3, 480 - 489, 31.12.2022

Bilal Koşar , Burak Tan , Melek Altunkaya , Cem Süer , Nurcan Dursun

https://doi.org/10.26559/mersinsbd.1096963

Abstract

Aim: In this study, it was aimed to reveal that the healing effect of selenium on spatial learning and memory performance impaired by hypothyroidism with 6-n-propyl-2-thiouracil in rats. Method: The study was carried out on young male Wistar albino rats weighing between 250 and 300 gr. The rats were divided into four groups which were control, hypothyroid, 5 ppm selenium supplied with 6-n-propyl-2-thiouracil and 10 ppm selenium supplied with 6-n-propyl-2-thiouracil group. Plasma fT3 and fT4 levels of rats were measured by ELISA method and hippocampus selenium levels were measured by atomic absorption spectrometry. Morris water maze test was used to evaluate learning/memory performance. Results: A significant decrease was observed in distance moved and escape latency of all groups from the first day to the fourth day of the learning test. In the statistical comparison between groups, distance moved showed an increase in the hypothyroid groups than that the control group and decrease in 10 ppm selenium supplemented hypothyroid group compared to hypothyroidism without selenium. The ratio of presence in the target quadrant decreased with hypothyroidism and increased in the group supplemented 5 ppm selenium compared to hypothyroidism without selenium. Conclusion: This study revealed that hypothyroidism may negatively affects hippocampal learning and memory function, and selenium supplementation may improve this negative effect of hypothyroidism.

Keywords

Hypothyroidism, selenium, learning, memory, morris water maze test

Sıçanlarda 6-n-propil-2-tiourasil ile bozulan öğrenme ve bellek performansına selenyumun etki

Abstract

Amaç: Bu çalışma ile sıçanlarda 6-n-propil-2-tiourosil (PTU) ile hipotiroidi oluşturularak bozulan uzamsal öğrenme ve bellek performansına selenyumun (Se) iyileştirici etkisini ortaya koymak amaçlanmıştır.
Gereç ve Yöntem: Çalışma vücut ağırlıkları 250-300 gr olan, genç erkek Wistar albino sıçanlar üzerinde yapıldı. Sıçanlar kontrol (Kontrol), hipotiroidi (PTU), PTU ile berabler 5 ppm Se verilen (P-5Se) ve PTU ile berabler 10 ppm Se verilen (P-10Se) olarak dört gruba ayrıldı. Sıçanların plazma sT3, sT4 değerleri ELİSA yöntemiyle, hipokampus Se değerleri ise atomik absorpsiyon spektrometresi ile ölçüldü. Öğrenme/bellek performansının değerlendirilmesi için Morris su tankı testi (MST) kullanıldı.
Bulgular: Öğrenme testinin ilk gününden dördüncü güne doğru tüm grupların yüzme mesafelerinde ve kaçış sürelerinde anlamlı düzeyde azalma görüldü. Gruplar arası istatistiksel karşılaştırmada yüzme mesafesi uygulamanın birinci gününde hipotiroidili grupta kontrole göre artış, Se verilen hipotiroidili gruplarda azalma bulundu. Hedef kadranda bulunma oranı hipotiroidi ile azalma, 5 ppm Se verilen grupta, Se verilmeyen hipotiroidili gruba göre artış gösterdi.
Sonuç: Bu çalışma hipotiroidinin hipokampal öğrenme ve bellek fonksiyonunu olumsuz etkilediğini, selenyum takviyesinin ise hipotirodinin bu olumsuz etkisini düzelttiğini ortaya koymuştur.

Keywords

Hipotiroidi, Selenyum, Öğrenme, Bellek, Morris su tankı testi, Hypothyroidism, selenium, learning, memory, morris water maze test

References

• Keleş E, Çepni S. Beyin ve öğrenme. J. Turk. Sci. Educ. 2006;3(2):66-82.
• Morris RG, Garrud P, Rawlins Ja, O'Keefe J. Place navigation impaired in rats with hippocampal lesions. Nature. 1982;297(5868):681-3.
• Bavarsad K, Hosseini M, Hadjzadeh M-A-R, Sahebkar A. The effects of thyroid hormones on memory impairment and Alzheimer's disease. J Cell Physiol. 2019;234(9):14633-40.
• Artis A, Bitiktas S, Taşkın E, Dolu N, Liman N, Suer C. Experimental hypothyroidism delays field excitatory post‐synaptic potentials and disrupts hippocampal long‐term potentiation in the dentate gyrus of hippocampal formation and Y‐maze performance in adult rats. J. Neuroendocrinol 2012;24(3):422-33.
• Jo S, Fonseca TL, Bocco BMLC et al. Type 2 deiodinase polymorphism causes ER stress and hypothyroidism in the brain. J. Clin. Investig. 2019;129(1):230-45.
• Huang SA, Dorfman DM, Genest DR, Salvatore D, Larsen PR. Type 3 iodothyronine deiodinase is highly expressed in the human uteroplacental unit and in fetal epithelium. J. Clin. Endocrinol. Metab. 2003;88(3):1384-8.
• Winther KH, Rayman MP, Bonnema SJ, Hegedüs L. Selenium in thyroid disorders — essential knowledge for clinicians. Nat. Rev. Endocrinol 2020;16(3):165-76.
• Croteau W, Whittemore SL, Schneider MJ, Germain DL. Cloning and expression of a cDNA for a mammalian type III iodothyronine deiodinase. Int. J. Biol. Chem. 1995;270(28):16569-75.
• Ventura M, Melo M, Carrilho F. Selenium and thyroid disease: from pathophysiology to treatment. Int. J. Endocrinol 2017;2017.
• Arthur JR, Nicol F, Hutchinson AR, Beckett GJ. The effects of selenium depletion and repletion on the metabolism of thyroid hormones in the rat. Journal of inorganic biochemistry 1990;39(2):101-8.
• Chaalal A, Poirier R, Blum D et al. PTU‐induced hypothyroidism in rats leads to several early neuropathological signs of Alzheimer's disease in the hippocampus and spatial memory impairments. Hippocampus. 2014;24(11):1381-93.
• Bitiktaş S, Tan B, Batakçı M, Kavraal Ş, Dursun N, Süer C. Effects of selenium treatment on 6-n-propyl-2-thiouracil-induced impairment of long-term potentiation. Neurosci. Res. 2016;109:70-6.
• Gilbert M, Sui L. Dose-dependent reductions in spatial learning and synaptic function in the dentate gyrus of adult rats following developmental thyroid hormone insufficiency. Brain Res. 2006;1069(1):10-22.
• Bal C, Büyükşekerci M, Ercan M ve ark. Farklı selenyum seviyelerinin tiroid hormon sentezi üzerine etkisi. Turk Hij Den Biyol Derg, 2015; 72(4): 311-6.
• Dias GRM, Vieira FA, Dobrachinski F et al. Diphenyl diselenide diet intake improves spatial learning and memory deficits in hypothyroid female rats. Int. J. Dev. Neurosci. INT J DEV NEUROSCI 2012;30(2):83-9.
• Meydani M. Antioxidants and cognitive function. Nutr. Rev. 2001;59(8):S75-S82.
• Lee KH, Cha M, Lee BH. Neuroprotective Effect of Antioxidants in the Brain. Int. J. Mol. Sci. 2020;21(19):7152