Effect Of Nanomaterials On The Membrane Potential Of Mouse Early Embryonic Cells And Its Effect On The Structure Of Mouse Oocytes

Due to the increasingly widespread application of nanomaterials,many studies on the toxic effects of nanomaterials on organisms have been reported.Mitochondrial oxidative stress,ROS production and accumulation,activation of apoptotic proteins and endoplasmic reticulum stress are all pathways through which nanomaterials produce toxic effects on organisms.The cell membrane is the first line of defense of cells against external harmful substances and is the guarantee of normal cellular life activities.Therefore,the effect of nanomaterials on cell membranes is the first problem to be solved for nanomaterials application in biomedical field.The cell membrane potential is considered to be an important parameter reflecting cell metabolic activity and cell viability,and is also an important indicator to evaluate the state of cell membrane.In the existing studies,it has been shown that nanomaterials can cause depolarization of bacterial cell membrane and change the cell membrane potential of somatic cells,but the effect on the membrane potential of embryonic cells wrapped by zona pellucida is not clear.Therefore,we speculate that when early embryos come in contact with nanomaterials,it may have an effect on the cell membrane and alter the cell membrane potential in a very short period of time.In order to elucidate the effects of nanomaterials on the membrane potential of early mammalian embryonic cells and on the structure of oocytes,mouse early embryos were selected as the material for this study,and a model was established to study the alteration of nanomaterials on the membrane potential of early embryonic cells.The effects of different particle sizes and concentrations of nano-silver,exposure of other nano-materials(nano-gold,nano-copper and nano-carbon)on the membrane potential of prokaryotic embryonic cells and the effects of nano-silver on the membrane potential of embryonic cells at different developmental stages,as well as the effects of short-term exposure(1 h)of nano-gold and nano-silver on the ultrastructural changes of mouse oocytes were analyzed to determine the effects of nano-silver and nano-gold on early embryonic cell membranes.In this study,we used laser confocal scanning technique to detect the alteration of embryonic cell membranes under different environmental conditions by staining early embryos with Di BAC4(3)membrane potential-sensitive fluorescent dye,and transmission electron microscopy and ultrathin sectioning techniques to study the structural alteration of oocytes by nanogold and nanosilver.It was found that nanosilver had an immediate effect on the membrane potential of protoplast embryos,i.e.,it caused depolarization of embryonic cells and an increase in membrane potential within a short period of time(5 min),and its effect on the membrane potential of embryonic cells was negatively correlated with the particle size of nanosilver and positively correlated with the dose;nanogold,nanocopper and nanocarbon did not cause any change in the membrane potential of protoplast embryos within a short period of time(30 min).Nanogold,nano-copper and nano-carbon did not cause any change in membrane potential of embryonic cells at the prokaryotic stage for a short period of time(30min);nano-silver caused an increase in membrane potential of embryonic cells at different developmental stages.In the 1 h oocytes of the nanogold and nanosilver treated group,the structure of the oocytes was intact,and the organelles in the cytoplasm were found to have an uneven matrix and high local electron density.The mitochondria of the 1 h group treated with nanosilver were intact,and the mitochondria were not obviously swollen,but the matrix was slightly uneven,the cristae were slightly broken,the endoplasmic reticulum was mildly expanded,and the nanosilver particles were visible in the cytoplasm;in the 3 h group treated with nanosilver,the mitochondrial damage was aggravated compared with that of the 1 h group,and most of the mitochondria showed uneven matrix and elevated electron density,and most of the endoplasmic reticulum was moderately expanded.The mitochondrial matrix was uneven and the local electron density was elevated.The above findings showed that: nanosilver has the ability to cause membrane potential alteration in prokaryotic embryonic cells and other developmental period embryonic cell membrane alteration,but other nanomaterials did not cause membrane potential alteration in prokaryotic stage embryonic cells,and the alteration of nanosilver on early embryonic cell membrane potential showed negative correlation with its particle size and positive correlation with the dose size;at short-term exposure,the effect of nanosilver on oocyte subcellular structure showed a temporal effect,while the effect of nanogold on oocyte structure did not increase with increasing exposure time.