Qirong Tablets inhibits apoptosis of ovarian granulosa cells via PI3K/Akt/ HIF-1 signaling pathway

Abstract

This study aims to observe the effect and explore the mechanism of Qirong Tablets in the treatment of premature ovarian insufficiency(POI) in mice via the phosphatidylinositol 3-kinase(PI3K)/protein kinase B(Akt)/hypoxia inducible factor 1(HIF-1) signaling pathway. Sixty SPF female BALB/c mice were randomly divided into normal group, model group, positive control group, Qirong Tablets low-, medium-and high-dose group. The normal group was intraperitoneally injected with the same amount of normal saline, and the other groups were intraperitoneally injected with cyclophosphamide 120 mg·kg~(-1)·d~(-1) once to establish a POI animal model. After the model was successfully established, the low-, medium-and high-dose groups of Qirong Tablets were administered orally with 0.6, 1.2, 2.4 mg·kg~(-1)·d~(-1) respectively. The positive control group was given 0.22 mg·kg~(-1)·d~(-1) Clementine Tablets by intragastric administration, and the normal group and model group were given intragastric administration with the same amount of normal saline, and the treatment was 28 d as a course of treatment. After drug intervention, enzyme-linked immunosorbent assay(ELISA) was employed to measure the levels of estradiol(E_2), follicle-stimulating hormone(FSH), luteinizing hormone(LH), and anti-mullerian hormone(AMH) in peripheral blood, and hematoxylin-eosin(HE) staining to observe the ovarian tissue. Terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling(TUNEL) assay was used to detect the apoptosis of granulosa cells, and Western blot to determine the expression levels of B-cell lymphoma-2(Bcl-2), Bcl-2-associated X protein(Bax), caspase-3, PI3K, Akt, and HIF-1. Compared with the normal group, the modeling of POI caused loose or destroyed ovarian tissue with vacuolar structures, edema and fibrosis in the ovarian interstitium, disordered or loose arrangement of granulosa cells, and reduced normal follicles. Compared with the model group, drug interventions restored the ovarian tissue and follicles at all the development stages and reduced atretic follicles. Compared with the normal group, the modeling of POI lowered the serum level of E_2 and AMH(P<0.01), and elevated the level of FSH and LH(P<0.01). Compared with the model group, high-dose Qirong Tablets elevated the levels of E_2 and AMH(P<0.05), and lowered the levels of FSH and LH(P<0.05). Compared with the normal group, the modeling of POI up-regulated the protein levels of PI3K, Akt, HIF-1, Bax, and caspase-3 and down-regulated the protein level of Bcl-2 in the ovarian tissue(P<0.01). Compared with the model group, low-, medium-, and high-dose Qirong Tablets down-regulated the protein levels of PI3K, Akt, HIF-1, Bax, and caspase-3 proteins and up-regulated the protein level of Bcl-2 in the ovarian tissue(P<0.05). In conclusion, Qirong Tablets can up-regulate the expression Bcl-2, down-regulate the expression of Bax and caspase-3 in POI mice. Qirong Tablets may inhibit the apoptosis of follicular granulosa cells in mice, thereby delaying ovarian aging, improving reproductive axis function, and strengthening ovarian reserve capacity, which may be associated with the inhibition of PI3K/Akt/HIF-1 pathway.