RESUMO
This study was conducted on twenty healthy female balady rabbits to investigate the histological structure of the rabbit ovary at different physiological conditions, in addition to evaluate cytokeratin 7 localization in this organ. The animals were classified into four groups each comprised five animals: neonates, adult non-pregnant non-lactating, adult pregnant and adult lactating rabbits. Upon sacrifaction, ovaries samples were prepared for general histological structure and with improved Biotin-Streptavidin amplified detecting staining methods to localize the sites of intermediate filaments cytokeratin 7. Moreover, minute parts were prepared for transmission electron microscope examination.Light microscopic examination of the ovarian sections showed an outer broad cortex and an inner narrow medulla with no line of demarcation in between. Also, a dense tunica albuginea was organized under the covering epithelium and appeared well developed in adult pregnant rabbit ovary. The cortex, in neonates contained only primordial follicles which differentiated to various ovarian follicles at adult ages. But, it was noticed that atretic follicles were found more abundant in the ovarian cortex during pregnancy. The medulla was formed of fibrovascular connective tissue stroma which became more vascular with pregnancy. The corpus luteum of pregnancy was large in size and accounted for more than one half the volume of the ovary and characterized by the presence of numerous lipid droplets in the small luteal cells cytoplasm. The ovarian interstitial tissue was ill developed at neonate stage. While, in adult age it appeared formed of polygonal cells with pale cytoplasm and rounded nuclei. With pregnancy they became hypertrophied with vacuolated cytoplasm and vesicular nuclei. The ovary of lactating female was similar in its histological structure to that of the cyclic one. In conclusion, the present study showed that rabbit ovaries at different physiological conditions had its own characteristic histological features which suit its functional demands. Cytokeratin 7 was found to be represented in the ovarian surface epithelium, all stages of follicular development, oocyte, luteal cells and in the medullary stroma mainly around the blood vessels. So, from this study, it could be recommended that cytokeratin 7 could be used as a tumour marker to distinguish different types of ovarian tumours