Skiers, hikers, soldiers and others exposed to extreme cold temperatures may experience frostbite because of the rather painful injuries that occur when ice crystals form in the skin. Many extremely cold areas are also remote, and delays in frostbite treatment can lead to severe wounds, scarring and even having to face amputation.
Now, researchers published in the JOURNAL ACS Applied Biomaterials have developed a cream that prevents frostbite when applied to the skin of mice 15 minutes before severe cold exposure.
Frostbite not only kills skin cells, but also damages deeper tissues, such as muscles and bones, sometimes causing secondary infections and permanent nerve damage. Common treatments, such as rapid reheating of the affected limb, aim to reverse tissue freezing, but many cells are actually frozen to death at the time of treatment. Recently, scientists have developed frostbite prevention strategies, such as electric heaters sewn into clothing or genetically modified antifreeze proteins, but these methods are often costly, impractical, or have safety issues. Therefore, Munia Ganguli and colleagues hope to test the frostbite prevention properties of synthetic molecular combinations commonly used in cryopreservation cells in laboratories. Dimethyl sulfoxide (DMSO) allows ice crystals to form within cells, while polyvinyl alcohol (PVA) prevents ice crystals from forming in the space between cells, which can damage cell membranes.
The researchers first tested the ability of different amounts of DMSO and PVA, either alone or in combination, to prevent the death of cultured cells exposed to freezing temperatures. They found that a combination of 2 percent DMSO with 1.6 mg/ml of PVA yielded the highest cell survival rate (about 80 percent) while protecting cell membranes and cytoskeletons. This combination, which the researchers call SynAFP, not only has a protective effect, but also allows cells to divide and express proteins more normally after cold stress. The team then mixed SynAFP with a commercial aloe vera cream and applied it to mouse skin 15 min before the cold challenge. Compared with no treatment, the ointment reduces the wound size, tissue damage and inflammation of frostbite, and accelerates healing. Not enough, this method does not prevent frostbite when using the ointment 30 minutes or more before the cold challenge; the good news is that the ointment is used multiple times without damaging the skin. The researchers say the effects of this newly formulated frost on people, and how often it takes to reapply it, still needs to be studied to determine.