Effects of Heyan Kuntai Capsule () on Follicular Development and Oocyte Cohesin Levels in Aged Mice.

Objective: To evaluate the effect of Heyan Kuntai Capsule (, HYKT) on the ovarian function of aged mice and expressions of cohesion complexes in oocytes.

Methods: Twenty-five 9-month-old female C57BL/6J mice were randomly divided into 5 groups by block randomization method (n=5 per group), including the control group (saline), 17β-estradiol group [E, 100 μg/(kg•d)], and low-, medium-, and highdose of HYKT groups [0.3, 0.9, 2.7 g/(kg•d), respectively]. All mice were treated by intragastric administration for 4 weeks. Hematoxylin and eosin staining and anti-VASA staining were used to detect the amounts of follicles. The apoptosis of follicles was measured by anti-gamma HA histone family member X (γHAX) staining and TdT-mediated dUTP Nick-End Labeling (TUNEL) assay. The density of cohesin subunits, REC8 meiotic recombination protein (REC8), structural maintenance of chromosome (SMC) 1β and SMC3 in oocytes were evaluated by immunofluorescent staining.

Results: After administration of E and high-dose of HYKT, the total number of follicles as well as the number of primordial and primary follicles were significantly increased (P<0.05). Anti-γHAX staining and TUNEL assay demonstrated that high-dose of HYKT and E partly suppressed the apoptosis of follicles (P<0.05). Furthermore, it showed an increased trend in the levels of REC8 and SMC1β, after administration with E and HYKT, and no obvious change in the level of SMC3.

Conclusion: HYKT could enhance the number of follicles, suppress apoptosis of oocytes and have a trend to elevate the meiotic-specific cohesin subunits (REC8 and SMC1β) in oocytes of aged mice, indicating a beneficial effect on the ovarian function in terms of the quantity and quality of follicles.