Jerusalem, March 20th
Scientists have developed a new method for growing mouse embryos outside the womb at early stages of development, an advance that will provide new insights into how genes affect the process, and potentially lead to new mechanisms for understanding birth defects.
According to the researchers, including Jacob Hanna from the Weizmann Institute of Science in Israel, current methods for studying mammalian embryonic development include both monitoring the process in mammals, such as frogs or fish that lay visible eggs, or receiving static images from mouse embryos and combining them.
In the current study, published in the journal Nature, the latter scientists were able to grow early-stage embryos outside the uterus through trial and error over a span of nearly seven years, mimicking and double-examining the process.
The researchers came up with a two-step method in which they could grow normally developing mouse embryos outside the uterus for six days – about a third of their 20-day gestation period – and at that time the plan embryos have a clear body and visible organs.
“For us, that is the most mysterious and exciting part of innovative development, and we can now look at it and try it out in detail,” said Hanna.
In the first phase, which lasted about two days, the scientists started with mouse embryos several days old after they were inserted into the uterus.
At this stage, they said the embryos were balls containing 250 unidentified gas cells, and were placed on a special growth medium in a laboratory basin, and the team got the balls to attach to this medium as they would to the uterine wall.
With this step, the researchers doubled the first stage of initial development, in which the embryo doubles and triples in size as it differs in three layers – a- inside, middle and outside.
After this, as the embryos entered the next stage of development, which involves the formation of organs from each of the layers, they required additional conditions.
In this second step, the scientists placed the primroses in a nutrient solution in tiny bakeries, mounted on rollers that kept the solutions stirring and mixing regularly, the study noted. .
According to the researchers, the mixture helped keep the embryos, which were growing without maternal blood flow to the placenta, sticking in the nutrients.
With further experiments, the scientists said they had learned to control the gases, oxygen and carbon dioxide – not just the amounts, but the gas pressure as well.
In later stages, they inserted the embryos genes that identified the growing organs in fluorescent dyes – an attempt that suggested the success of further experiments with this system. , including various genetic and other treatments, reliable results.
“We believe that you can inject genes or other elements into the cells, alter the conditions or infect the embryo with a virus, and the system we have shown will give you results that are compatible with development inside a mouse uterus, “Hanna said.
“If you give an embryo the right position, its genetic code acts as a pre-set line of dominoes, designed to fall in a row,” he said.
Using this method, the scientists hope to answer such questions as why there is so little incontinence, why the window for implantation is so short, and what the conditions are. the pregnancy that can cause developmental disorders.
The researchers believe that the new method will reduce the cost and speed up the study process in the field of developmental biology and reduce the need for laboratory animals. PTI