The Expression And Significance Of Sirtuins In Ovaries Of Mice With Different Models

?Objective? To explore the relationship between ovarian function and the expression of sirtuins in ovaries of mice with physiological ovarian aging and mice subjected to caloric restriction and chemotherapy.?Methods? Mice with physiological ovarian aging are different age groups of C57BL/6 adult female mice aged either 2 months,8 months or 18 months.For the CR model,6-week old adult female mice were randomly divided into 2 groups: a normal control(NC)group(fed ad libitum)and the 25% caloric restriction(CR)group(fed with 75% of the food of the NC group).Ovaries were harvested after 8 weeks of treatment.For the chemotherapy model,adult female mice aged 6 weeks were given a single intraperitoneal injection of 500 ?L phosphate buffered saline(PBS)containing CTX 120 mg/kg,control group were given a single intraperitoneal injection of an equal volume PBS.Ovaries were collected 7 days after CTX treatment.Their ovaries were harvested,and the right-side ovaries were snap frozen and stored at-80 °C for protein extraction,while the left-side ovaries were fixed in 4% paraformaldehyde for histological sectioning.Ovarian sections were subjected to routine hematoxylin-eosin(HE)staining for histological observation,the numbers of follicles at each stage were counted to estimate ovarian reserve.The expression of SIRT1,SIRT3 and SIRT6 in the ovaries of different mice were analyzed by Western blotting.The relationship between ovarian expression levels of sirtuin proteins(SIRT1,SIRT3,and SIRT6)and the primordial follicle numbers of the mice was further analyzed using linear regression.?Results?Histological analysis showed that a gradual decline in the number of follicles(especially primordial follicles)was observed in aging mice and mice subjected to chemotherapy,while CR mice displayed a significantly greater number of primordial follicles and less atretic follicles.Western blot analysis indicated that the expression levels of SIRT1,SIRT3 and SIRT6 in the ovaries of aged mice and mice treated with chemotherapy were significantly decreased,but increased in CR mice.Linear regression analysis showed that the expression of SIRT1,SIRT3 and SIRT6 in ovaries was significantly positively correlated with the number of primordial follicles(P <0.001).?Conclusion? The expression levels of SIRT1,SIRT3 and SIRT6 in ovaries of mice were significantly correlated with the size of primordial follicles pool,indicating that these sirtuins are closely related to ovarian reserve and suggesting that they may be used as new molecular markers for ovarian aging.