Reproductive toxicology最新文献

Granulosa cells are an important component of the ovary, surrounding the oocytes. The structural characteristics of ovarian follicles limit blood perfusion, thereby naturally forming an endogenous hypoxic microenvironment within the granulosa cell - oocyte complex. External hypoxic exposure (such as in high-altitude environments) further exacerbates the hypoxic condition of the ovary, making the regulation of low oxygen on the biological functions of granulosa cells a growing focus in reproductive biology and reproductive toxicology research. In this review, we systematically summarize and analyze the various impacts of hypoxia on the core physiological processes of granulosa cells (including proliferation, apoptosis, luteinization, and steroidogenesis), emphasizing the typical molecular signaling pathways that mediate these hypoxia-induced effects. We note that hypoxia is a double-edged sword in ovarian physiology: it regulates the adaptive physiological responses of granulosa cells to support normal follicle development, but excessive or persistent hypoxia can cause granulosa cell dysfunction and damage the development of ovarian follicles. Analyzing the exact hypoxia-mediated regulatory mechanisms in granulosa cells not only deepens our understanding of ovarian physiological homeostasis but also provides new insights into the mechanisms of hypoxia-related ovarian reproductive diseases.

Nanoplastics (NPs), plastic particles smaller than 1 μm, have gained increasing attention due to their potential health effects. Experimental studies in animals have shown that NPs can pass biological barriers, reach the female reproductive tract, and enter the ovary. Their presence in the ovary might have profound consequences for reproductive endpoints, such as oocyte development. This study aimed to investigate the uptake and associated effects of polystyrene (PS) NPs on oocyte and embryo development using a bovine in vitro fertilization (IVF) model. Bovine cumulus-oocyte complexes (COCs) were exposed to pristine PS-NPs (50 nm or 200 nm) at different doses during in vitro maturation (23 h), followed by IVF and embryo culture. RNA sequencing was performed to investigate mechanisms involved in possible effects on oocyte maturation. Confocal microscopy confirmed the internalization of 50 nm and 200 nm PS-NPs into cumulus cells, however, only 50 nm particles were able to transfer into oocytes. Additionally, exposure to 50 nm PS-NPs at 3 μg/mL significantly delayed oocyte nuclear maturation and early embryo development. At this dose, RNA sequencing did not identify differentially expressed genes in the COCs, however, gene set enrichment analyses did indicate effects on mitochondrial processes. Nevertheless, subsequent analysis on mitochondrial activity remained unaffected. Our findings suggest that while 50 nm PS-NPs can penetrate the zona pellucida and impair oocyte maturation, their effects may not be driven by major transcriptomic or mitochondrial functional alterations.

RNAscope is a novel quantitative in situ gene expression assay that allows single molecule visualization and preservation of spatiotemporal and cell specific information across intact tissue samples. This method has utility to measure gene expression using intact tissue; thus, allowing quantification in a spatial and cell type specific manner, which can be valuable to complement single cell sequencing approaches that use disaggregated tissue. The accurate quantitative capacity of RNAscope depends on retention of RNA integrity which can be lost with extensive or poor tissue handling procedures. This protocol outlines a method of processing and carmine staining mammary gland whole mounts, which is commonly used to identify developmental and reproductive morphologies or disease lesions, followed by excision of tissue areas of interest and RNAscope on tissue sections. This method preserves both RNA integrity and accurate quantification of the RNAscope technology, while bypassing a need for labor-intensive screening of serial sections to identify unpalpable disease lesions induced by environmental exposures at various stages of reproductive development.

Maternal exposure to fine particulate matter (PM_2.5) correlates with low birthweight. The mechanism, however, remains elusive. We thus investigated the effects of maternal PM_2.5 exposure on maternal uterus and placenta. To this end, female C57BL/6 J mice were exposed to filtered air (FA) or concentrated ambient PM_2.5 (CAP) for 20 weeks and then mated with normal males. Placentas and fetus of gestation day 18.5 were harvested and analyzed. Pregnancy outcomes were also assessed, and after weaning, the uteri of those subgroups of dams were collected and analyzed either at estrus or diestrus stage. Maternal CAP exposure significantly reduced the fetal and placental weights but not fetal-placental weight ratio. Histological analysis of placenta showed smaller junction zone and bigger decidua due to maternal CAP exposure, accompanied by uterine natural killer (uNK) cell infiltration in decidua but not remarkable changes in vasculature and mRNA expression of nutrient transporters. Moreover, CAP exposure reduced uterine mass and increased uterine macrophage infiltration at estrus, but not diestrus, stage. As such, we demonstrate that PM_2.5 exposure provokes endometritis, which may be responsible for the development of placental abnormalities and fetal growth restriction due to maternal PM_2.5 exposure, shedding light on the mechanism whereby maternal PM_2.5 exposure causes adverse reproductive outcomes.