Objective:To evaluate the effect of Heyan Kuntai Capsule(和颜坤泰胶囊,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),17 β,-estradiol group [E2,100 μ g/(kg·d)],and low-,medium-,and high-dose 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 H2A histone family member X (γH2AX)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) 1 β and SMC3 in ooCytes were evaluated by immunofluorescent staining.Results:After administration of E2 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-γ H2AX staining and TUNEL assay demonstrated that high-dose of HYKT and E2 partly suppressed the apoptosis of follicles (P＜0.05).Furthermore,it showed an increased trend in the levels of REC8 and SMC1 β,after administration with E2 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 SMC1 β) in oocytes of aged mice,indicating a beneficial effect on the ovarian function in terms of the quantity and quality of follicles.