Menstrual blood-derived stem cell exosomes improve ovarian function in chemotherapy-Induced POF rats via apoptosis regulation

Recent studies have demonstrated that exosome therapy can promote the recovery of ovaries in premature ovarian failure (POF) models, which may aid in fertility restoration. This study aimed to investigate the therapeutic efficacy of exosomes derived from menstrual blood-derived mesenchymal stem cells (MenSCs-Exos) in a POF rat model, exploring its underlying mechanisms and detecting the optimal effective therapeutic dose. A POF model was established by an alkylating agent cyclophosphamide (CTX). All POF rats were divided into four groups (eight rats per group) and received a single intervention via the tail vein: phosphate-buffered saline (PBS), low-dose MenSCs-Exos (0.5 mL), middle-dose MenSCs-Exos (1 mL), high-dose MenSCs-Exos (2.0 mL). The concentration of MenSCs-Exos was 1 × 109 particles/mL. Serum was collected from the tail vein before CTX injection and on the 14th day after MenSCs-Exos treatment to measure the serum levels of follicle-stimulating hormone (FSH), luteinizing hormone (LH), anti-Müllerian hormone (AMH), and estradiol (E2) via ELISA. The ovarian pathology and follicle counts were examined by H&E. The protein expression and concentration of B-cell lymphoma-2(Bcl-2) and Bcl-2 associated X protein (Bax) in ovarian tissue were examined by western blot and ELISA. Rats in the middle- and high-dose MenSCs-Exos groups recovered their physical condition after treatment, and their body weight was significantly higher than that of the placebo group but lower than that of the control group, respectively ( P < 0.05). Compared to the placebo group, serum E2 and AMH levels were significantly increased, while serum FSH and LH levels were decreased (P < 0.05). MenSCs-Exos treatment also improved ovarian tissue morphology, and the number of follicles at all stages was markedly increased compared with those in the placebo group ( P < 0.05). In addition, the expression of anti-apoptotic Bcl-2 protein was significantly up-regulated and the expression of pro-apoptotic Bax protein was markedly inhibited after treatment, and the Bcl-2/Bax ratio was also significantly increased ( P < 0.05). Finally, the middle-dose achieved optimal therapeutic effect among the three MenSCs-Exos groups, as the low-dose achieved a less effective outcome and the high-dose exerted no additional therapeutic effects. MenSCs-Exos transplantation could effectively restore ovarian function and promote ovarian regeneration in Chemotherapy-induced POF model, whose mechanism is mainly associated with the regulation of apoptotic-related proteins expression. Additionally, the effective dose is middle-dose MenSCs-Exos (1 mL) or 1 × 109 particles in POF rats. Nevertheless, all these findings require further clinical validation in human models.