JERUSALEM, Aug. 2 (Xinhua) -- Israeli scientists have created an artificial model of mouse embryos without using an egg, sperm or uterus, the Weizmann Institute of Science (WIS) said Monday.
According to the study published Monday by the journal Cell, the mouse embryo model was developed from stem cells that were grown outside the mouse womb to a relatively advanced stage, showing normal development of organs and tissues, the WIS said in a statement.
This innovative approach may reduce the use of animals in research, and even become a reliable source of cells, tissues and organs for transplantation, the WIS noted.
The model was based on an effective method previously developed at the WIS, of returning embryonic stem cells to the most initial developmental stage, where they can differentiate into extra-embryonic tissues, including the placenta and yolk sac that support the development of the embryo.
In the new study, the scientists grew embryos that originated from embryonic stem cells that had been grown for years in culture.
The team treated the stem cells for 48 hours to increase the expression of certain genes necessary for the creation of extra-embryonic tissues.
As a result, some artificial mouse embryos developed similarly to natural embryos, with the placenta and yolk sac formed separately from the embryo.
They grew for eight and half days, almost half of the 20-day mice gestation period, developing early internal organs and a beating heart, the beginnings of blood circulation, a well-formed brain, rudimentary versions of a central nervous system and a digestive system.
"Our next challenge is to understand how the stem cells know what to do, how they organize into organs and how they find their way into the developing embryo," the researchers said. ■
