Abstract
Despite the well-studied role of tryptophan in the body, the literature data of its effect on the morpho-functional state of the thyroid gland are single and ambiguous. Preferably, the concentration of thyroid hormones in the blood after the tryptophan administration was studied. At the same time, the
morphological changes in the thyroid under its influence remain little studied. The aim of the study was to investigate the morphological changes in the rat thyroid gland after tryptophan administration. Material and methods. The study was carried out on 24 male Wistar rats aged 3 months. Rats of all groups were
under uniform conditions and standard diet. Animals of the experimental group, daily for 28 days, orally received L-tryptophan (France) at a dose of 80 mg/kg. Preparation of animals for experiments and invasive intervention were carried out in accordance with the principles of the Helsinki Declaration. Histological preparations were made from the central areas of the thyroid tissue by the standard method. The micropreparations were photographed using a digital camera of Nikon Microscope ECLIPSE E100 («Nikon Instruments Inc.», Japan). Morphometry was performed using a computer program «Image J». Statistical processing was carried out by methods of variation statistics. Results. An unchanged physiological structure of the rat thyroid gland was revealed in animals
taking L-tryptophan by histological analysis. The follicles had mostly the oval shape and various sizes. The follicular colloid was of moderate density with numerous resorption vacuoles. Thyrocytes had prismatic and cubic form. It was found a decrease of the follicular area, colloid, their inner diameter, and an increase in the stereological index of resorption and follicular-colloidal index and decrease of the colloid accumulation index. It noted also that there was the
decrease of relative area of the stroma in the gland, the stromalparenchymal index, the width of the interlobar, interlobular and interfollicular connective tissue. Conclusions. Prolonged (28 days) administration of L-tryptophan (at a dose of 80 mg/kg) to rats leads to the appearance of morphological signs of thyroid activation.
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