The effect of monosodium glutamate on the morphofunctional state of the thyroid gland in an experiment

Authors

DOI:

https://doi.org/10.26641/1997-9665.2024.3.117-123

Keywords:

thyroid gland, monosodium glutamate, pituitary thyroid-stimulating hormone, free thyroxine, microscopic structure, white rat, experiment.

Abstract

Background. Clinical observations and numerous studies do not provide a clear answer regarding the safe dose of the food additive monosodium glutamate (MSG). The least studied is the effect of MSG on the thyroid gland. Objective. To evaluate the effect of prolonged consumption of monosodium glutamate on the morphofunctional state of the thyroid gland in adult male Wistar rats. Methods. The experimental study was conducted on 20 adult male Wistar rats of reproductive age, which received MSG in their diet at a dose of 0.07 g/kg with free access to water. The first group of animals was examined after 4 weeks of the experiment, and the morphofunctional state of the thyroid gland was assessed by determining hormone levels in the blood: free thyroxine (fT4) and pituitary thyroid-stimulating hormone (TSH). After 10 weeks of the experiment, the second group of animals was examined, with the same parameters evaluated as in the first group. Results. After 4 weeks of MSG administration, the thyrocytes, as in the control group, were cubic in shape, located on the basement membrane, forming the follicular wall. The nuclear chromatin was distributed homogeneously, the nuclei were basophilic, and the cytoplasm was oxyphilic. Interfollicular cells were present in the interfollicular connective tissue areas. The follicles were surrounded by capillaries and contained oxyphilic-stained colloid. In all areas of the thyroid gland, the follicles were filled with colloid, and lymphoid cell clusters were found in the interfollicular areas. TSH and fT4 levels were determined by radioimmunoassay. The TSH concentration was 0.66±0.11 mIU/L, and free thyroxine (fT4) was 20.26±0.82 pmol/L. At this stage, both values showed no significant deviations. After 10 weeks of the experiment, it was observed that peripherally located functional follicles contained preserved colloid; however, the amount was minimal, and it poorly absorbed the dye. The absence of colloid in the follicular lumen, along with uneven follicular walls with protrusions, was noted. Some thyrocytes were displaced into the follicular lumen, deforming their shape. The cell membrane was indistinct, and the nuclei showed signs of pyknosis. The interfollicular spaces contained diffusely distributed lymphocytes and macrophages. Large clusters of lymphoid cells were found in some areas. The TSH concentration was 0.08±0.02 mIU/L (p<0.001), and free thyroxine (fT4) was 30.8±1.51 pmol/L (p<0.001), indicating a marked hyperproduction of TSH and excessive synthesis of free thyroxine. Conclusion. Thus, the use of monosodium glutamate at the administered dose of 70 mg/kg during prolonged consumption promotes the development of thyroid pathology, significantly increasing the concentration of pituitary thyroid-stimulating hormone and causing a pronounced excess of free thyroxine.

References

  1. Gruppen EG, Kootstra-Ros J, Kobold AM, et al. Cigarette smoking is associated with higher thyroid hormone and lower TSH levels: the PREVEND study. Endocrine. 2020;67(3):613-622. doi:10.1007/s12020-019-02125-2
  2. Brdar D, Gunjača I, Pleić N, et al. The effect of food groups and nutrients on thyroid hormone levels in healthy individuals. Nutrition. 2021;91-92:111394. doi:10.1016/j.nut.2021.111394
  3. Kayode OT, Bello JA, Oguntola JA, Kayode AAA, Olukoya DK. The interplay between monosodium glutamate (MSG) consumption and metabolic disorders. Heliyon. 2023;9(9):e19675. doi:10.1016/j.heliyon.2023.e19675
  4. Miskowiak B, Partyka M. Effect of neonatal treatment with MSG (monosodium glutamate) on thyroid of the adult male rats. Histol Histopathol. 1999;14(1):63-67. doi:10.14670/HH-14.63
  5. Mondal M, Sarkar K, Nath PP, Paul G. Monosodium glutamate suppresses the female reproductive function by impairing the functions of ovary and uterus in rat. Environ Toxicol. 2018;33(2):198-208. doi:10.1002/tox.22508
  6. Ishii S, Amano I, Koibuchi N. The Role of Thyroid Hormone in the Regulation of Cerebellar Development. Endocrinol Metab (Seoul). 2021;36(4):703-716. doi:10.3803/EnM.2021.1150
  7. Babić Leko M, Gunjača I, Pleić N, Zemunik T. Environmental Factors Affecting Thyroid-Stimulating Hormone and Thyroid Hormone Levels. Int J Mol Sci. 2021;22(12):6521. Published 2021 Jun 17. doi:10.3390/ijms22126521
  8. Hoermann R, Pekker MJ, Midgley JEM, Dietrich JW. The role of supporting and disruptive mechanisms of FT3 homeostasis in regulating the hypothalamic-pituitary-thyroid axis. Ther Adv Endocrinol Metab. 2023;14:20420188231158163. doi:10.1177/20420188231158163
  9. Jeger M, Sloot YJE, Horst RT, et al. Thyrotrophin and thyroxine support immune homeostasis in humans. Immunology. 2021;163(2):155-168. doi:10.1111/imm.13306
  10. Sirikul W, Sapbamrer R. Exposure to pesticides and the risk of hypothyroidism: a systematic review and meta-analysis. BMC Public Health. 2023;23(1):1867. doi:10.1186/s12889-023-16721-5
  11. Bílek R, Dvořáková M, Grimmichová T, Jiskra J. Iodine, thyroglobulin and thyroid gland. Physiol Res. 2020;69(2):S225-S236. doi:10.33549/physiolres.934514.
  12. Mateshuk-Vaceba LR, Garapko TV, Kirik HA, Blishchak NB, Primachenko VІ, Pіdval’na UE, et al, inventors; Lʹvivsʹkyy natsionalʹnyy medychnyy universytet imeni Danyla Halytsʹkoho, assignee. Sposіb modelyuvannya eksperimental’nogo alіmentarnogo ozhirіnnya oposeredkovanim vplivom glutamatu natrіyu. Ukrainian patent UA 144191. 2020 Sep 10. Int. CI. Ukrainian.
  13. Litvak YuV, Kochmar NYu, Holovatskyi AS, Getsko OI, Zavadska MB. [Morphological and morphometric studies of the structural components of the exocrine part of the rat pancreas under the influence of monosodium glutamate]. Morphologia. 2023;17(4):27-33. Ukrainian. doi: 10.26641/1997-9665.2023.4.27-33
  14. Harapko TV. [Submicroscopic changes of the spleen under the action of monosodium glutamate and correction with melatonin]. Morphologia. 2020;14(3):22-28. Ukrainian. doi: 10.26641/1997-9665.2020.3.22-28
  15. Harapko T, Mateshuk-Vatseba L, Goncharuk-Khomyn M, Bekesevych A, Lytvak Yu. Changes in the Structural Organization of Lymph Nodes and Biochemical Indicators of Blood Due to the Action of Sodium Glutamate. Journal of International Dental and Medical Research. 2020;13(4):1578-1584.
  16. Sodomora O. The Effect of Monosodium Glutamate Consumption on Carotid Sinus Morphology: an Electron Microscopy Experimental Study. Вісник проблем біології та медицини. 2022;4(167):316–321. DOI 10.29254/2077-4214-2022-4-167-316-321

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Published

2024-10-30

How to Cite

Svyatoska , L. (2024). The effect of monosodium glutamate on the morphofunctional state of the thyroid gland in an experiment. Морфологія / Morphologia / Morfologìâ, 18(3), 117–123. https://doi.org/10.26641/1997-9665.2024.3.117-123

Issue

Vol. 18 No. 3 (2024)

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