Unraveling the mechanism of long-term bisphenol S exposure disrupted ovarian lipids metabolism, oocytes maturation, and offspring development of zebrafish

Bisphenol S (BPS) acts as a xenoestrogen and disturbs the female reproductive system; however, the underlying mechanism has not been elucidated. In this study, the effect of chronic BPS exposure (1 μg/L and 100 μg/L) on ovarian lipid metabolism in zebrafish was investigated to determine its influence on adult reproductive capacity and offspring development. The results showed that long-term (240 days) exposure to BPS induced lipid accumulation in the ovaries by promoting the transport of more lipids from the circulation to the ovaries and by upregulating triacylglycerol synthesis-related genes. Significantly increased expression of cpt2, acadm, acadl, and pparα, which are involved in β-oxidation in the ovarian mitochondria, indicated that more energy was provided for oocyte maturation in exposed zebrafish ovaries. Thus, the proportion of full-grown stage oocytes in ovaries and egg reproduction were elevated at an accelerated rate, which earlier than normal reproductive cycle (8-10 days posts pawning). Moreover, the maternally BPS-exposed F1 embryos (2 h post-spawning, hpf) showed higher neutral lipid levels, impaired hatching capacity, and increased occurrence of larval deformities. All these findings demonstrated that stimulated lipid synthesis and β-oxidation in zebrafish ovaries significantly contribute to BPS-induced oocyte precociousness with subsequent effects on the development of unexposed offspring. This study provides new insight into the impact of xenoestrogens on oviparous reproduction in females and offspring development from the perspective of ovarian lipid metabolism.

Novel extra cellular-like matrices to improve human ovarian grafting

PURPOSE

To investigate if human ovarian grafting with pure virgin human recombinant collagen type-1 from bioengineered plant lines (CollPlant™) or small intestine submucosa (SIS) yields better implantation results for human ovarian tissue and which method benefits more when combined with the host melatonin treatment and graft incubation with biological glue + vitamin E + vascular endothelial growth factor-A.

METHODS

Human ovarian tissue wrapped in CollPlant or SIS was transplanted into immunodeficient mice with/without host/graft treatment. The tissue was assessed by follicle counts (including atretic), for apoptosis evaluation by terminal deoxynucleotidyl transferase assay and for immunohistochemical evaluation of neovascularization by platelet endothelial cell adhesion molecule (PECAM) expression, and for identification of proliferating granulosa cells by Ki67 expression.

RESULTS

Human ovarian tissue transplanted with CollPlant or SIS fused with the surrounding tissue and promoted neovascularization. In general, implantation with CollPlant even without additives promoted better results than with SIS: significantly higher number of recovered follicles, significantly fewer atretic follicles, and significantly more granulosa cell proliferation. Moreover, results with CollPlant alone seemed to be at least as good as those after host and graft treatments.

CONCLUSIONS

CollPlant is a biomaterial without any potential risks, and grafting ovarian tissue with CollPlant is easy and the procedure may be easily modified, with limited or no foreseeable risks, for auto-transplantation in cancer survivors. Further studies are needed using other novel methods capable of enhancing neovascularization and reducing apoptosis and follicle atresia.