Scientists have received most detailed images of human fetusesusing two common laboratory instruments, fluorescent dyes and laser microscopes. The method described in Cellallows you to study the first few days of development without genetic modification of embryos, writes the journal news service Nature.
“This is the first time we have been able to image a human fetus in its earliest stages of development. We can see individual cells and how they interact with each other to form a preimplantation embryo,” says Nicholas Plachta, a cell biologist at the University of Pennsylvania in Philadelphia, one of the authors of the study.
The method will help to conduct non-invasive screening of embryos conceived as a result of in vitro fertilization (IVF). Usually one has to study such embryos, killing some of them. Now, fluorescent dyes can simply be added to the sample to label specific cellular structures.
The embryos used in this study were donated for research through an IVF clinic. Each embryo is only 60–100 cells and does not yet have fully formed tissues or organs.
The researchers used SPY650-DNA, a fluorescent dye that marks genomic DNA, and SPY555-actin, which marks the protein F-actin, which forms the skeleton of cells. As a result, dozens of 40-hour live embryos using powerful laser scanning microscopes.
For example, researchers have noticed that cells in the outer layer, known as the trophectoderm, lose some of their DNA during cellular replication, called interphase. Such errors may be related to chromosomal abnormalities, and this embryo will not take root during IVF. The authors are confident that the new method will help determine which embryo has the greatest potential for implantation in IVF.
The authors were also able to compare key developmental events in human and mouse embryosto her (the latter is often used in research) and noticed some important differences. For example, a process called densification, which involves changes in cell shape, begins at 12 cells in human embryos and 8 cells in mice. These small differences can make a big difference in development.
2023-07-07 14:20:45
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