Estrous cycle dependent changes in expression and distribution of Fas, Fas ligand, Bcl-2, Bax, and pro- and active caspase-3 in the rat ovary

• Published in: Journal of endocrinology Vol. 188; no. 2; pp. 179 - 192
• Main Authors: Slot, Karin A, Voorendt, Marsha, de Boer-Brouwer, Mieke, van Vugt, Harmke H, Teerds, Katja J
• Format: Journal Article
• Language: English
• Published: Colchester BioScientifica 01.02.2006; Portland Press
• Subjects: Animals; Apoptosis - physiology; bcl-2-Associated X Protein - analysis; Biological and medical sciences; Caspase 3; Caspases - analysis; chorionic-gonadotropin; corpora-lutea; Corpus Luteum - metabolism; corpus-luteum; Epithelial Cells - metabolism; Estrus - metabolism; Fas Ligand Protein; fas Receptor; Female; follicular atresia; Fundamental and applied biological sciences. Psychology; granulosa-cells; growth-factor-i; Hormone metabolism and regulation; Immunohistochemistry - methods; induced apoptosis; luteal immune cells; Luteolysis - metabolism; Mammalian female genital system; Membrane Glycoproteins - analysis; messenger-ribonucleic-acid; Ovarian Follicle - growth & development; Ovary - metabolism; Ovulation - metabolism; Proto-Oncogene Proteins c-bcl-2 - analysis; Rats; Rats, Wistar; Receptors, Tumor Necrosis Factor - analysis; Regular papers; RNA, Messenger - analysis; Signal Transduction - physiology; surface epithelial-cells; Tumor Necrosis Factors - analysis; Vertebrates: reproduction; Ovary; Vertebrata; Mammalia; Rat; Female genital system; Rodentia; Adult animal; Female; Estrous cycle; Gene expression; Localization; Apoptosis
• ISSN: 0022-0795; 1479-6805
• DOI: 10.1677/joe.1.06165

In the present investigation, the localization of proteins involved in ovarian apoptosis were studied throughout the estrous cycle in the presence of fluctuating hormone levels. Fas, Fas ligand, Bcl-2, Bax and caspase-3 mRNA expression and proteins were detected in all ovarian tissue extracts, though the amount of protein varied with the phase of the estrous cycle. Fas, Bax and caspase-3 protein levels were highest at diestrus and decreased thereafter towards metestrus. In contrast, Fas ligand and Bcl-2 protein levels were lowest at diestrus and increased toward metestrus. Immunohistochemistry revealed that the staining of the anti-apoptotic protein Bcl-2 was more pronounced in healthy preantral follicles than in atretic follicles. In contrast, the pro-apoptotic proteins Fas, Fas ligand, Bax and active caspase-3 were more predominantly present in atretic follicles. In the ovarian surface epithelium (OSE), Fas, procaspase-3 and Bcl-2 immunostaining appeared independent of the phase of the estrous cycle. Fas ligand and Bax staining was detected particularly during proestrus in OSE cells surrounding the ovulatory follicles, while active caspase-3 was observed only in OSE cells at the postovulatory site during estrus. The proportion of luteal cells that stained positively for Fas, Bax and caspase-3 increased with the age of the corpus luteum, while Fas ligand and Bcl-2 immunostaining was strongest in newly formed corpora lutea and decreased thereafter. In conclusion, the components of the Fas signalling pathway were differentially expressed throughout the estrous cycle in a variety of ovarian cell types, which may correspond to hormone dependent survival mechanisms.