Scientists create the first in vitro embryos using vitrified African Lion oocytes
Scientists from Germany’s Leibniz Institute for Zoo and Wildlife Research, Givskud Zoo – Zootopia in Denmark and University of Milan, Italy have succeeded in creating the first African lion in-vitroembryos through the vitrification of immature oocytes. In this method of cryopreservation the oocytes from an animal are immediately frozen in liquid nitrogen at 196degC after it has been castrated or died. This technique allows for the storage of oocytes from valuable animals indefinitely, so they can be used with assisted reproduction techniques to produce offspring. It is hoped that these techniques can be improved and applied to save endangered species like the Asiatic Lion from extinction. In this regard, the current research using African lions to model species is a significant step. The results of the research are published in Cryobiology, a scientific journal.
Due to their high lipid contents, it is believed that lion oocytes have a very sensitive response to cooling. This results in a poor recovery after slow cooling. This problem can be avoided by vitrification, where the cells are frozen very quickly in solutions containing a high concentration of cryoprotective agent. This method stops the formation of ice in the cells that could damage them and allows them to be used later.
Scientists collected oocytes for this research from four African Lionesses at Givskud Zoo – Zootopia, after they had been euthanised to manage the population. The vitrification of half the oocytes was instantaneous. After six days in liquid nitrogen storage, the vitrified eggs were thawed out and in-vitromaturated in an incubator for 32-34hrs at 39degC. The other half of the oocytes (59) was used as a control group, and were directly exposed toin-vitromaturation in an incubator at 39degC without a step vitrification. The mature oocytes from both groups were fertilized using frozen-thawed male African lion sperm. We could show a high percentage of mature oocytes and surviving oocytes among the vitrified oocytes. Nearly 50% of the oocytes had matured. This is similar to the proportion in the control group, says Jennifer Zahmel.
Source:
https://phys.org/news/2021-01-scientists-in-vitro-embryos-vitrified-african.html
