Structural, functional, and lectin histochemical characteristics of rat ovaries and endometrium in experimental hyper- and hypothyroidism

Abstract

Twenty lectins with different carbohydrate affinities, including five new lectins purified from fungi,
were used for histochemical examination of carbohydrate determinants in rat ovaries and endometrium under
experimental hyper- and hypothyroidism. In the ovaries of control rats, lectin binding was detected predominantly
in the zona pellucida and corona radiata of growing follicles, luteocytes, and leucocytes. Within the endometrium,
lectins reacted strongly with the luminal surface, epitheliocytes and secretions of the uterine glands,
pre-decidual cells, leucocytes, and collagen fibers. As revealed on general morphology and estrous cycle studies,
hyperthyroidism induced ovarian luteinization, and increased the content of pre-decidual cells and of collagen
fibers in the endometrium, with no reliable effect on the estrous cycle. Hypothyroidism was accompanied by
retardation of the estrous cycle, enhanced folliculogenesis and leucocyte infiltration of ovarian and endometrial
stroma. Both hyper- and hypothyroidism significantly affected the tissue carbohydrates of the ovaries and endometrium:
specific and differential redistribution of DMan, LFuc, NeuNAc, DGlcNAc, DGalNAc, and DGal
determinants was detected under both pathological conditions. Hyperthyroidism induced more severe alterations
of glycoconjugates than hypothyroidism; the endometrium was more susceptible to thyroxin-modulated
impairments than the ovaries. These results give new insights into the pathogenetic mechanisms of the effects of
thyroid disorders on the female reproductive organs and demonstrate the suitability of lectin histochemistry
methods for monitoring the efficacy of hormonal imbalance correction therapy, as well as the applicability of
new lectin preparations for the selective labeling of ovarian and endometrial constituents.