Background: Cyclophosphamide is a widely utilized chemotherapeutic agent for pediatric cancers, known to elicit adverse effects, including perturbation of the PI3K/Akt/mTOR and Hippo signaling pathways, thereby diminishing ovarian reserve and fertility potential in females. Consequently, this investigation delves into the mitigative effects of metformin on cyclophosphamide-induced ovarian impairment in prepubertal mice. Methods: Twenty-four 14-day-old NMRI female mice were distributed into four groups: Control (Cont), Cyclophosphamide (Cyc), Metformin (Met), and Metformin plus Cyclophosphamide (Met-Cyc). The Met-Cyc group was given daily doses of 150 mg/kg metformin for 11 consecutive days and in parallel 3 intermittent doses of 65 mg/kg cyclophosphamide once every three days. The Met and Cyc groups were given identical doses of Met or Cyc alone. The control group received normal saline treatment. On the 12^th day, mice were sacrificed for analysis. Stereological methods were employed to measure the overall volume of the ovaries, including the medulla, cortex, and follicles, along with measuring anti-Müllerian hormone (AMH) levels using an ELISA kit. Furthermore, qRT-PCR was utilized to quantify the expression levels of genes, including P53, Bax, Bcl-2, Rad-51, Pten, Mtor, and Yap-1. Results: The findings demonstrate that metformin ameliorates cyclophosphamide-induced ovarian toxicity by increasing AMH levels and attenuating the excessive activation of primordial follicles, the ratio of growing to quiescent follicles, and follicular atresia. This protective effect is mediated by the downregulation of apoptosis-related genes, upregulation of the gene involved in a reparative pathway, and modulation of the PI3K/Akt/mTOR pathway evidenced by increased expression of Pten, Mtor and Hippo pathway by Yap-1 expression. Conclusions: Our results advocate for the potential of metformin as a viable therapeutic option for preserving ovarian function in cyclophosphamide-treated adolescent girls, given its favorable side effect profile and ability to improve cyclophosphamide-induced ovarian damage.

We examined the effects of DNA methyltransferase inhibitor – RG108, and histone deacetylase inhibitor – SAHA, on the reprogramming parameters of cloned mouse embryos produced by somatic cell nuclear transfer into oocytes. The programming parameters studied included dynamics of histone reacetylation, developmental rate, DNA methylation, and transcript levels of genes, all of which are pivotal to lineage specification and blastocyst formation. At the pronuclear stage, somatic nucleus-transplanted oocytes treated with 5 µM SAHA presented higher histone acetylation at H3K9, H3K14, H4K16 and H4K12, compared to untreated clones (p < 0.05). At the morula stage, cloned embryos treated with 5 μM RG108 or 5 μM SAHA presented lower DNA methylation intensity compared to untreated clones (p < 0.05), resembling the intensity levels of fertilized embryos. However, these effects were not observed when RG108 and SAHA were used in combination. The rate of morula formation was significantly higher in cloned embryos treated with 5 µM SAHA than in untreated clones, whereas treatment with RG108 resulted in no obvious effects on morula formation rates. On the other hand, the combined treatment with RG108 and SAHA resulted in inferior rates of cloned morula formation, compared to untreated clones. At the blastocyst stage, the aberrant expression levels of key developmental genes Oct4 and Cdx2, but not Nanog, were corrected in cloned embryos by the treatment with RG108. This is similar to the intensity levels seen in fertilized embryos. The expression of Rpl7l1 gene was significantly higher in embryos treated with both RG108 and SAHA than in untreated and in control groups. In summary, the present study showed that SAHA and RG108, when applied separately, improve the rate and quality of cloned mouse embryos.

The objective of this study was to induce the differentiation of human theca stem cells (hTSCs) into germ cell-like cells (hGCLCs) and assess their developmental progression following in vitro 3D culture with ovarian somatic cells within the follicle-like structures. To achieve this, the hTSCs were isolated from small antral follicles of three patients of varying ages and were then seeded in a differentiation medium for 40 days. The differentiated hGCLCs were subsequently aggregated with somatic ovarian cells (cumulus cells and hTSCs) in a ratio of 1:10 and cultured in a growth medium in a suspension culture dish. In addition to examining the morphologies, sizes, and viabilities of the differentiated hGCLCs, this study also analyzed the expression of DAZL and GDF9 proteins within the follicle-like structures. After 12 days, the hTSCs began to differentiate into hGCLCs, with their shapes changing from spindle-shaped to spherical. The sizes of hGCLCs increased during the differentiation period (from 25 μm to 50 μm). The survival rate of the hGCLCs after differentiation and in vitro development in primordial follicle-like structures was 54%. Unlike hTSCs, which did not express the DAZL protein, the hGCLCs and follicle-like structures successfully expressed DAZL protein (P-value < 0.05). However, hGCLCs poorly expressed the GDF9 protein. Further, the culture of hGCLCs in primordial follicle-like structures significantly increased GDF9 expression (P-value < 0.05). In conclusion, our study demonstrated that 3D cultures with ovarian somatic cells in follicle-like structures caused the successful differentiation of reproducible hGCLCs from hTSCs derived from three patients of different ages. Moreover, this method not only enhanced the in vitro development of hGCLCs but also presented a novel approach for co-culturing and developing in vitro oocyte like cells, ultimately leading to the production of artificial follicles.