[Protective effect of moxibustion on ovarian function in mice with premature ovarian insufficiency based on...

To investigate whether the protective effect of moxibustion on ovarian function in mice with premature ovarian insufficiency (POI) was associated with mitochondrial dynamics and function in ovarian granulosa cells, using a mitochondrial fission activator.

Eighty female ICR mice with regular estrous cycles were randomly divided into a blank group, a tripterygium glycosides group (TG group), a moxibustion group, and a carbonyl cyanide m-chlorophenyl hydrazone plus moxibustion group (CCCP+moxibustion group), with 20 mice in each group. Except for the blank group, POI model was established in the remained groups by intragastric administration of TG suspension for 14 consecutive days. In the moxibustion group, moxibustion was applied at bilateral "Shenshu" (BL23) or alternately at "Zhongwan" (CV12) and "Guanyuan" (CV4) 1 hour after TG administration, once every day for 14 days. The CCCP+moxibustion group received intraperitoneal injection of CCCP (2.9 mg·kg^-1·d^-1) after TG administration, followed by the same moxibustion protocol as the moxibustion group. Estrous cycles were recorded, and the ovarian index was calculated. Ovarian morphology was observed with HE staining, and follicle counts were conducted. Serum levels of follicle-stimulating hormone (FSH), estradiol (E₂), and anti-Müllerian hormone (AMH) were measured using ELISA. Immunohistochemistry and real-time quantitative PCR were used to detect the protein and mRNA expression of mitochondrial dynamics-related factors (dynamin-related protein 1 [Drp1], mitochondrial fission factor [Mff], optic atrophy 1 [Opa1], and mitofusin 1 [Mfn1]) in the ovaries, respectively. ATP concentration in granulosa cells was determined by luciferase assay, and reactive oxygen species (ROS) fluorescence intensity was detected using DCFH-DA fluorescent probe method.

Compared with the blank group, the mice in the TG group showed a significantly higher rate of estrous cycle disorder (P<0.01), smaller ovarian volume, lower ovarian index (P<0.01), reduced numbers of primordial, growing, and antral follicles (P<0.01), increased number of atretic follicles (P<0.01), and loose and disordered arrangement of granulosa cells; serum FSH level was elevated (P<0.01), while serum AMH and E₂ levels were reduced (P<0.01). Drp1 and Mff protein staining in ovarian granulosa cells was intensified, while Opa1 and Mfn1 protein staining was lighter. The average optical densities of Drp1 and Mff and the mRNA expression of Drp1 and Mff were significantly increased (P<0.01), while the average optical densities of Opa1 and Mfn1 and the mRNA expression of Opa1 and Mfn1 were significantly decreased (P<0.01). ATP concentration was reduced (P<0.01), and ROS fluorescence intensity was decreased (P<0.01). Compared with the TG group, the mice in the moxibustion group exhibited lower rate of estrous cycle disorder (P<0.01), larger ovarian volume, higher ovarian index (P<0.01), increased numbers of primordial, growing, and antral follicles (P<0.01), reduced number of atretic follicles (P<0.01), and a more compact and orderly arrangement of granulosa cells; serum FSH level was decreased (P<0.01), while serum AMH and E₂ levels were increased (P<0.01). Opa1 and Mfn1 protein staining was deepened, Drp1 and Mff protein staining was lightened, average optical densities and mRNA expression of Opa1 and Mfn1 were increased (P<0.01, P<0.05), and those of Drp1 and Mff were decreased (P<0.05, P<0.01). ATP concentration was increased (P<0.01), and ROS fluorescence intensity was decreased (P<0.01). Compared with the moxibustion group, the mice in the CCCP+moxibustion group showed an increased estrous cycle disorder rate (P<0.05) and a decreased ovarian index (P<0.05). The numbers of primordial, growing, and antral follicles were reduced (P<0.01, P<0.05), while the number of atretic follicles was increased (P<0.01). The arrangement of ovarian granulosa cells became looser and more disordered. Serum FSH level was elevated (P<0.01), while serum E₂ and AMH levels were decreased (P<0.05). In the ovaries of mice in the CCCP+moxibustion group, Drp1 and Mff protein staining was intensified, whereas Opa1 and Mfn1 protein staining was lighter. The average optical densities of Drp1 and Mff, as well as the mRNA expression levels of Drp1 and Mff in granulosa cells, were increased (P<0.05), while the average optical densities of Opa1 and Mfn1 and the mRNA expression levels of Opa1 and Mfn1 in granulosa cells were decreased (P<0.05, P<0.01). Additionally, the ATP concentration in ovarian granulosa cells was reduced (P<0.01), and the ROS fluorescence intensity was elevated (P<0.01).

Moxibustion may alleviate TG-induced ovarian damage by inhibiting mitochondrial fission and promoting mitochondrial fusion, thereby improving impaired mitochondrial function; this protective effect can be blocked by CCCP.