动物实验 z-bo 2020-09-11 369

　　In a study published in the journal Cell a few days ago, artificial embryos without sperm and eggs were transplanted into female mice to form the first female mice, but these embryos were still malformed. This artificial mouse embryo is formed from the scratch by a special kind of stem cells called expanded pluripotent stem cells. They can produce all three cell types found in early embryos. Jun Wu of the University of Texas Southwestern Medical Center and his colleagues soaked stem cells in nutrients and growth promoters to convert the stem cells into three embryonic cell types and self-assemble them into embryo-like structures. Then, the researchers transplanted artificial embryos into the uterus of female mice and successfully transferred 7% of the embryos. A week later, scientists used royal incisions to excise the transferred embryos. Microscopic examination showed that despite the serious deformities, they began to form early fetal structures. This experiment is the first time that an artificial embryo develops into fetal tissue in the womb. Other research groups have used stem cells to create artificial mouse embryos, but these embryos have not been successfully transplanted into the uterus or can only form other types of placental cells after transplantation. Cells cannot.

　　The challenge here is to fine-tune the artificial mouse embryo to grow into a complete fetus. Wu said this may include cultivating a mixture of nutrients and growth promoters to bring the embryos closer to the environment that is normally exposed to the human body.

　　But Mr. Wu also said that the reason for this is to prevent offspring from reproducing. By testing the ability of artificial embryos to grow in the uterus, humans can see their authenticity. When deemed realistic enough, researchers can use them to replace actual embryos usually obtained from mice. Wu said: "Our goal is to have a scalable system that can produce hundreds or thousands of embryo-like structures." At the same time, embryo models can be studied in a petri dish to better understand mammalian Early development, optimization of in vitro fertilization conditions, and screening of drugs that may cause birth defects.