Effect Of Sirt1on Apoptosis Of Porcine Granulosa Cells

Follicular atresia is a general feature in all mammalian ovaries. The overwhelming majority of follicles undergo atresia during follicular development in mammalian ovaries, and only a few follicles can maturate and ovulate. In multiparous animals such as porcine, follicle atresia affect the ovulation rate and litter size. Therefore, there has a basilic production and economy meaning in research of follicle atresia. Follicle atresia is a extremely complex physiological process which regulated by endocrine. The main mechanism of follicle atresia is begin with the apoptosis of granular cell. SIRT1is known as a member of SIR2family, which is an NAD+-dependent histone deacetylase. SIRTUINS catch the attention of people due to their function on extending lifespan in yeast and mammalians. Recent years, the research suggest that SIRT1has crucial roles in regulating a variety of molecular and cellular processes including anti-stress, neuronal protection, calorie restriction, glucose metabolism, fat storage and insulin secretion; and its effect in cell apoptosis is explained gradually. According to the published reports, this study was designed to explore the roles of SIRT1on the apoptosis of granulosa cells in the porcine ovary, which may provide a basis for the study of follicular atresia.In this research, the porcine ovary is chosed as the material, the research was mainly focused on these aspects:(1)Detection the expression and location of SIRT1in porcine ovary by Immunohistochemistry; Analysis the expression of SIRT1in different cells in the ovary, disparate phage of growing follicles and different phage atretic follicles respectively. The fluorescent quantitation PCR was used to detect the mRNA level of SIRT1in different phase of growing follicles and atretic follicles respectively.(2)Culture granular cells in vitro, the activator(RES) and inhibitor(NAM) was used to process the granular cells respectively, and induced apoptosis by non-serum culture media. The flow cytometry was used to detect the apoptosis rate in each group; The MTT was used to detect the cell proliferation in each group.The main results are as follows: 1. The expression of SIRT1was mainly located in oocytes, granular cells, theca cells, lutein cells; and the expression level of SIRT1in granular cells is significantly higher than in the theca cells; SIRT1is also detected in some of the lutein cells; It’s hardly to find the expression of SIRT1in interstitial cells. The cellular localization of SIRT1in ovary is nucleus.2. The expression of SIRT1in different growing phase follicles showed variability, it’s highest in3-1.5mm diameter follicles, and decreased along with follicle growing. The expression of SIRT1mRNA increased during atresia. Immunohistochemical study showed that the protein expression of SIRT1was increased in granular cells during atresia, which to hint the important roles of SIRT1in the process of granular cell apoptosis.3. The culture of granular cells in vitro was designed to further investigating the relationship between SIRT1and granular cell apoptosis. Suppress the expression of SIRT1, the apoptosis rate of granular cell was dramatically decreased, and the proliferation of cells was rised; Enhance the expression of SIRT1, the apoptosis rate of granular cell was increased, and the proliferation of cells was descent. These results indicate that SIRT1may regulate follicle atresia through encouraging granular cell apoptosis.