Kidney-tonifying formula facilitates the development and maturation of mouse preantral follicle in vitro.

Objective: Kidney-tonifying formulas are frequently used in clinical practices to enhance follicular development and maturation. This research explored the impacts of the Bushen Tiaojing formula (BSTJF) on the development of mouse preantral follicles and its relationship with granulosa cells and gonadotropins.

Methods: Preantral follicles were extracted from mice and cultured with or without serum from rats that were previously treated with or without BSTJF. During cultivation, the follicles were monitored for morphological changes and developmental maturation. Exhausted medium was collected every other day for the measurement of progesterone and estradiol (E) levels by ELISA. Granulosa cells in medium were collected on days 8, 10, and 12 and analyzed for determining the expressions of apoptosis-associated genes (, and ). Propagation and apoptosis rates of collected granulosa cells were measured by CCK-8 assay and flow cytometry.

Results: Compared with control follicles, follicles cultured with serum from BSTJF-treated rats had a higher survival rate, larger follicle diameter, higher expression, and lower and expressions (all ≤ 0.05). In addition, their granulosa cells presented substantially elevated proliferation ( ≤ 0.05) and a lower rate of apoptosis ( ≤ 0.05) compared with granulosa cells from control follicles. The level of E in the culture media of all groups increased slowly in the first 6 days. Subsequently, after formation of the antrum, the levels of E and progesterone were enhanced in the medium of follicles cultured with serum from BSTJF-treated rats compared with those in the media of control follicles (all ≤ 0.05).

Conclusion: Serum from BSTJF-treated rats facilitated the development and maturation of mouse follicles by increasing the expression of anti-apoptotic gene , reducing the expressions of pro-apoptotic genes and as well as the apoptosis of granulosa cells, promoting the proliferation of granulosa cells and increasing the secretion of E and progesterone in the cells.