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Herla, Franziska (2014): Immunhistochemische, glykohistochemische und ultrastrukturelle Untersuchungen am Ovar der Katze (Felis catus). Dissertation, LMU München: Faculty of Veterinary Medicine



In my thesis 25 feline ovaries (Felis catus) were studied using histological, glycohistochemical, immunhistochemical and ultrastructural methods. Additionally to the different follicle stages, the ovarian stroma and the thecal glands were also evaluated. For the glycohistochemical investigations, an appropriate panel of lectins was used, including Concanavalin Agglutinin (Con A), Wheat germ Agglutinin (WGA), Wheat germ Agglutinin succinylated (WGAs), Sambucus nigra Agglutinin (SNA) , Pisum sativum Agglutinin (PSA), Ricinus communis Agglutinin (RCA), Viscum album Agglutinin (VAA), Phaseolus vulgatis Erythroagglutinin (PHA E), Maackia amurensis Agglutinin I (MAA I), Phaseolus vulgaris Leukoagglutinin (PHA L), Sophora japonica Agglutinin (SJA) and Griffonia simplicifolia Agglutinin I (GSA I). The most interesting glycohistochemical staining was the strong reaction of WGA in the zona pellucida and the surrounding corona radiata cells. The staining with WGA-FITC demonstrates N-acetylglucosamine and sialic acids in the zona pellucida and the surrounding corona radiata. The immunhistochemical examination using antibodies against cytokeratins, vimentin, laminin, desmin, synemin, tubulin, SMA, S100, connexin 43, ERα and progesterone receptors showed the localization of cytoskeletal components within the different compartments of the feline ovary and the distribution of steroid hormone receptors. The ovarian surface epithelium contains not only cytokeratins but also synemin and nuclear estrogen receptors. The interstitial gland cells show a strong immunohistochemical staining with antibodies against vimentin, S100 and connexin 43. A similar immunohistochemical staining pattern was also observed in cells of the theca interna of tertiary follicles. The immunohistochemical staining pattern differs between the luteal cells derived from granulosa cells (granulosa lutein cells) or from thecal cells (theca lutein cells). The small theca cells only showed a distinct reaction with tubulin and S100 antibodies, in contrast to the large luteal cells which reacted much more strongly. In the rete ovarii the expression of cytokeratins, tubulin, progesterone receptors and ERα could be immunohistochemically demonstrated. Oocytes of the follicles of different developmental stages only showed a positive reaction with the synemin antibody. At all developmental stages, the follicle cells showed a strong immunohistochemical staining with the tubulin antibody. The intensity of connexin immunostaining increased during follicular development within the follicular epithelium from primordial to tertiary follicles. This proves the increase in the number of gap junctions in the follicular epithelium during follicle growth. In contrast the staining intensity with the vimentin antibody decreased in granulosa cells from primordial to tertiary follicles. This may indicate the remodelling of the cytoskeleton of the granulosa cells in growing follicles to obtain steroidogenic potential. The formation of nuclear ERα and progesterone receptors varies under the influence of different hormones, depending on the ovarian cycle. The rete ovarii is the only structure in which both receptor types are expressed. ERα can be detected in granulosa cells of some primary follicles, as well as in the ovarian surface epithelium. Progesterone receptors are localized in the theca interna of tertiary follicles and in small luteal cells and fibrocytes of the corpus luteum. In conclusion the feline ovary shows, in comparison to other mammals, an early differentiation of cytoskeletal and glykan containing elements. The zona pellucida is already formed in primary follicles and the granulosa cells contain vimentin filaments and gap junctions, which can already be observed in the stage of primordial follicle. The distribution of the S100 protein in the ovary of the cat differs fundamentally from all other species investigated so far. S100 was predominantly found in steroidogenic cells and may indicate its involvement in steroidogenesis, in conjunction with the expression of vimentin and connexin.