Mechanism of microRNA-22-3p of extracellular vesicles derived from bone marrow mesenchymal stem cells in inhibiting damage of ovarian granulosa cells induced by cyclophosphamide

Objective To analyze the effect of microRNA-22-3p (miR-22-3p) of extracellular vesicles derived from bone marrow mesenchymal stem cells on premature ovarian failure.

Methods Follicular fluids were provided by premature ovarian failure patients with in vitro fertilization or the second-generation in vitro fertilization treatment and normal volunteers with the same treatment for infertility due to male factors; the exosomes derived from bone marrow mesenchymal stem cells were isolated by differential centrifugation; the morphology, particle size and marker proteins of isolated exosomes were analyzed by transmission electron microscopy, NanoSight LM10 analyzer and Western blotting. Granulosa cells were treated with cyclophosphamide (CTX), exosomes, miR-22-3 mimics and corresponding controls, and were divided into CTX group, control group, exosome incubation group, PBS treatment group, CTX+miR-22-3p group, CTX+miR-NC group, CTX+Exosomes group, and CTX+PBS group; gene expression was detected by Western blotting and quantitative real-time polymerase chain reaction (qRT-PCR). The 3-(4, 5-Dimethylthazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) reagent and flow cytometry were used to detect cell viability and apoptosis.

Results The extracted exosomes had typical goblet vesicles, the exosome marker proteins C cluster of differentiation 63 (CD63) and C cluster of differentiation 9 (CD9) were expressed in the extracted exosomes, and exosome particle size was 80 to 150 nm; miR-22-3p was significantly lowly expressed in patients with premature ovarian failure and ovarian granulosa cells induced by CTX (P < 0.05), but was significantly highly expressed in ovarian granulosa cells incubated with exosomes derived from bone marrow mesenchymal stem cells (P < 0.05); the activity of granulosa cells in the CTX group was significantly lower than that in the control group, but was significantly higher in the CTX+miR-22-3p group or CTX+Exosomes group than that in the control group (P < 0.05); the apoptosis rate of granulosa cells in the CTX group was significantly higher than that in the control group, but was significantly lower in the CTX+miR-22-3p or CTX+Exosomes group than that in the control group (P < 0.05).

Conclusion The miR-22-3p of extracellular vesicles derived from bone marrow mesenchymal stem cells can inhibit ovarian granulosa cell injury induced by CTX.