A small species of frog capable of surviving extreme temperature drops may hold the key to the creation of better freezing techniques for in vitro fertilization (IVF) treatments, a new study says.
Eastern wood frogs native to boreal forests in the United States are known to withstand freezing temperatures as low as -8 degrees Celsius (-14.4 degrees Fahrenheit) during winter. Despite becoming frozen throughout this period, these animals are still able to thaw themselves out by springtime and continue on without suffering any negative effects on their health.
This unique ability in eastern wood frogs is what researchers at the University of Leeds are trying to mimic in order to improve freeze storage methods typically used for food, drugs and fertility treatments.
Current techniques for storing IVF treatments sometimes result in losing samples because not all of the cells that were frozen can be recovered.
While several anti-freezing techniques for fertility treatment storage have been developed over the years, they were not quite as effective as cryoprotectants often seen in nature.
To solve this problem, researchers at Leeds identified a natural compound known as glycerol, which eastern wood frogs and other animals use to help protect themselves from freezing temperatures.
The team discovered that when glycerol is exposed to water and then cooled to -35 degrees C (-63 degrees F), the compound encapsulates the water molecules so that they wouldn't be able to form an icy network. These water molecules are reduced to low density forms that appear ready to freeze, but they don't.
Dr. Lorna Dougan, a researcher at Leeds' School of Physics and Astronomy and lead author of the study, explained that the experiments provide them with a better understanding on the basic properties of water.
The results of their study are crucial because they help raise questions regarding the presence of cryoprotectants in living organisms, such as eastern wood frogs, and how these organisms are able to use these compounds to survive.
"If we understand what glycerol is doing we might be able to fine-tune some of these cryoprotectants that are used to find more effective combinations," Dougan said.
Glycerol and other cryoprotectants play a key role in helping prevent tissues and cells from forming damaging ice crystals when they are stored in sub-zero temperatures.
The findings of the University of Leeds study are featured in the Journal of Physical Chemistry B.
