Smad 3 May Regulate Follicular Growth in the Mouse Ovary

• Published in: Biology of reproduction Vol. 66; no. 4; pp. 917 - 923
• Main Authors: TOMIC, D, BRODIE, S. G, DENG, C, HICKEY, R. J, BABUS, J. K, MALKAS, L. H, FLAWS, J. A
• Format: Journal Article
• Language: English
• Published: Madison, WI Society for the Study of Reproduction 01.04.2002
• Subjects: Animals; Apoptosis; bcl-2-Associated X Protein; bcl-X Protein; Biological and medical sciences; Body Weight; CDC2-CDC28 Kinases; Cell Division; Cell Survival; Cyclin-Dependent Kinase 2; Cyclin-Dependent Kinases - analysis; DNA-Binding Proteins - deficiency; DNA-Binding Proteins - physiology; Female; Fertility; Immunohistochemistry; Male; Mice; Mice, Knockout; Ovarian Follicle - cytology; Ovarian Follicle - growth & development; Ovary - anatomy & histology; Ovary - chemistry; Ovary - physiology; Proliferating Cell Nuclear Antigen - analysis; Protein-Serine-Threonine Kinases - analysis; Proto-Oncogene Proteins - analysis; Proto-Oncogene Proteins c-bcl-2 - analysis; Smad3 Protein; Trans-Activators - deficiency; Trans-Activators - physiology
• ISSN: 0006-3363; 1529-7268
• DOI: 10.1095/biolreprod66.4.917

Although Smad 3 is known to serve as a signaling intermediate for the transforming growth factor beta (TGFβ) family in nonreproductive tissues, its role in the ovary is unknown. Thus, we used a recently generated Smad 3 -deficient (Smad 3−/−) mouse model to test the hypothesis that Smad 3 alters female fertility and regulates the growth of ovarian follicles from the primordial stage to the antral stage. In addition, we tested whether Smad 3 affects the levels of proteins that control apoptosis, survival, and proliferation in the ovarian follicle. To test this hypothesis, breeding studies were conducted using Smad 3−/− and wild-type mice. In addition, ovaries were collected from Smad 3−/− and wild-type mice on Postnatal Days 2–90. One ovary from each animal was used to estimate the total number of primordial, primary, and antral follicles. The other ovary was used for immunohistochemical analysis of selected members of the B-cell lymphoma/leukemia-2 family of protooncogenes (Bax, Bcl-2, Bcl-x), proliferating cell nuclear antigen (PCNA), and cyclin-dependent kinase 2 (Cdk-2). The results indicate that Smad 3 −/− mice have reduced fertility compared with wild type mice. The results also indicate that Smad 3 may not affect the size of the primordial follicle pool at birth, but it may regulate growth of primordial follicles to the antral stage. Further, the results indicate that Smad 3 may regulate the expression of Bax and Bcl-2, but not Bcl-x, Cdk-2, and PCNA. Collectively, these data suggest that Smad 3 may play an important role in the regulation of ovarian follicle growth and female fertility.