Assessment of Functional Activity of the Bovine Thyroid Gland Using Morphometry, and Two Markers of Cellular Proliferation

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Jelinek F., I.Krabaaova, V. Kroupova: Assessment of Functional Activity of the Bovine Thyroid Gland Using Morphometry and Two Markers of Cellular Proliferation. Acta Vet. Brno 2003, 72:11-16. The aim of the study was to contribute to objectivity of morphological investigation of thyroid gland in cattle.Thyroid gland in euthyreoid cows is composed of conspicuously different size follicles. Using image analysis the follicles were classified in accordance to their diameter in three size categories: large (175.1-615 µm), medium, (80.1-175 µm) and small (15-80 µm). Moreover, there were considerable individually different proportions among the determined size categories of the follicles. Height of the follicular epithelium was in reverse relation to size of the follicles. Mean values were 7.06 µm, 8.04 µm and 8.39 µm, respectively. Proliferative activity of follicular epithelium, evaluated by means of proliferating nuclear antigen and nucleolar organizer regions was high in the small, moderate in the medium and low in the large follicles. We found these markers suitable for evaluation of proliferative activity of follicular cells in the bovine thyroid gland. Thyroid gland, functional activity, morphometry, proliferation Histological assessment of functional activity of the thyroid gland consists of estimation of size of the follicles, height of the follicular epithelium, quantity and colour of the colloid and proliferative activity of the epithelial cells. It is generally accepted that increased function of the thyreoidea manifest itself by smaller follicles, higher follicular epithelium, decreased quantity and eosinofilia of the colloid and by increased proliferative activity. Morphometry facilitates objective evaluation of morphological parameters of organs and tissues. It may be performed by micrometrical equipment installed in microscope or by means of computer technique with software for picture analysis. Results of morphometry of the thyroid gland using micrometer were published by KoAovaet al. (1998, 1999). Results obtained by image analysis were presented by Kratochvil (1998).