The morphogenesis of the skin in the progeny of hypothyroid female rats in pre- and postnatal ontogenesis was studied using general morphology and lectin histochemistry methods. The experiment was conducted on 20 female Wistar rats weighing 180-200 g, which were divided into two groups: control (10), and experimental (10), from which were obtained 70 and 46 offsprings, respectively. Experimental hypothyroidism was induced by daily food supplementation with antithyroid drug mercazolil at the rate 5 mg/kg of animal body weight. After the second week of the experiment, females in the estrus stage were paired with males. Skin samples from the back of experimental and control groups progeny rats were taken on the embryonic day 16, and on the postnatal days 1, 10, 20 and 40. Skin samples were fixed in 4% neutral formalin and embedded in paraffin. 5-7 μm thick sections were stained with hematoxylin and eosin. Carbohydrate determinants were detected using a set of lectin-peroxidase conjugates as follows: Con A, PNA, HPA, WGA, SNA, LABA and LTFA. Maternal hypothyroidism, alongside increased total body weight of progeny animals, induced hypodermal thickening, enhanced activity of granular cells layer and of keratinization processing. Rearrangement of lectin receptor sites included reduced reactivity of PNA, SNA and WGA, which play an important role in the formation of adhesive contacts between keratinocytes, and of DGal(β1- 3)DGalNAc and βDGal carbohydrate determinants in the sebaceous gland secretory products, which regulate proliferation and differentiation of cells of hair follicles.

Key words: Skin – Mercazolil – Hypothyroid rats progeny – Lectin histochemistry

   We studied the influence of maternal hypothyroidism on progeny skin morphogenesis by means of histological, histochemical and lectinhistochemical methods. Hypothyroid conditions in rats were achieved by daily food supplementation with antithyroid drug Mercazolil. The experiment was conducted on 10 control and 10 hypothyroid rats, which delivered 70 and 46 offsprings, respectively. We discovered that maternal hypothyroidism induces the accumulation of mast cells (MCs) in the skin of progeny on the 1st, 10th and 20th postnatal days, with decrease of these cell’s count returning to control level on 40th postnatal day. These results indicate that offsprings developing under conditions of maternal hypothyroidism are a risk group for changes in immune status and the occurrence of allergic reactions. The stratum corneum of epidermis, its lipid barrier as well as pilosebaceous units, in both control and experimental group animals, at the early stages of postnatal ontogenesis are enriched with carbohydrate determinants of αDMan, βDGal, βDGal(1–3)DGalNAc, αLFuc, αDGalNAc, αDGlcNAc, Neu5Ac. Galanthus nivalis agglutinin (GNA) is a selective histochemical marker of MCs, while Lactarius torminosus fungus agglutinin (LTFA) is a selective label of Langerhans cells. Maternal hypothyroidism resulted in reduction of lectin binding with the structural components of progeny skin and its derivatives. We speculate that alterations in glycoconjugate processing and degradation sequences have an impact on the cell signaling, formation of adhesive contacts, cellular proliferation and differentiation. The lectin set we used clearly demonstrated specific labeling of cellular subpopulations, monitoring glycoconjugates processing and degradation under physiological and pathological conditions in all skin components.
Keywords: skin, Mercazolil, hypothyroid rats’ progeny, lectin histochemistry.