Model construction and drug therapy of primary ovarian insufficiency by ultrasound-guided injection
Authors: Dai Fangfang , Liu Hua , He Juan , Wu Jinglin , Yuan Chaoyan , Wang Ruiqi , Yuan Mengqin , Yang Dongyong , Deng Zhimin , Wang Linlin , Wang Yanqing , Yang Xiao , Wang Huiling , Hu Wei , Cheng Yanxiang 
Published: February 2024

Abstract
Background
Clinically, hormone replacement therapy (HRT) is the main treatment for primary ovarian insufficiency (POI). However, HRT may increase the risk of both breast cancer and cardiovascular disease. Exosomes derived from human umbilical cord mesenchymal stem cell (hUC-MSC) have been gradually applied to the therapy of a variety of diseases through inflammation inhibition, immune regulation, and tissue repair functions. However, the application and study of hUC-MSC exosomes in POI remain limited.

Methods
Here, we first constructed four rat animal models: the POI-C model (the “cyclophosphamide-induced” POI model via intraperitoneal injection), the POI-B model (the “busulfan-induced” POI model), the POI-U model (the “cyclophosphamide-induced” POI model under ultrasonic guidance), and MS model (the “maternal separation model”). Second, we compared the body weight, ovarian index, status, Rat Grimace Scale, complications, and mortality rate of different POI rat models. Finally, a transabdominal ultrasound-guided injection of hUC-MSC exosomes was performed, and its therapeuticy effects on the POI animal models were evaluated, including changes in hormone levels, oestrous cycles, ovarian apoptosis levels, and fertility. In addition, we performed RNA-seq to explore the possible mechanism of hUC-MSC exosomes function.

Results
Compared with the POI-C, POI-B, and MS animal models, the POI-U model showed less fluctuation in weight, a lower ovarian index, fewer complications, a lower mortality rate, and a higher model success rate. Second, we successfully identified hUC-MSCs and their exosomes, and performed ultrasound-guided intraovarian hUC-MSCs exosomes injection. Finally, we confirmed that the ultrasound-guided exosome injection (termed POI-e) effectively improved ovarian hormone levels, the oestrous cycle, ovarian function, and fertility. Mechanically, hUC-MSCs may play a therapeutic role by regulating ovarian immune and metabolic functions.

Conclusions
In our study, we innovatively constructed an ultrasound-guided ovarian drug injection method to construct POI-U animal models and hUC-MSC exosomes injection. And we confirmed the therapeutic efficacy of hUC-MSC exosomes on the POI-U animal models. Our study will offer a better choice for new animal models of POI in the future and provides certain guidance for the hUC-MSCs exosome therapy in POI patients.

Graphical abstract
The schema of construction of different animal models, extraction and identifying hUC-MSCs and exosomes, therapy of ultrasound-guided hUC-MSCs exosome injection. Note: POI: premature ovarian insufficiency; hUC-MSCs: Human umbilical cord mesenchymal stem cells; POI-C: POI-cyclophosphamide; POI-B: POI-cyclophosphamide + Busulfan; POI-U: POI-Ultrasonic guidance cyclophosphamide injection; MS: POI-Maternal separation. POI-e: ultrasound-guided hUC-MSCs exosome injection; AMH: Anti-müllerian hormone; LH: Luteinizing hormone; FSH: Follicle-stimulating hormone; DA: dopamine; T: Testosterone; PRL: prolactin; GnRH: Gonadotropin-releasing hormone.