Non-permeating Cryoprotectants Research Articles

Cryoprotectants Protect Lipopolysaccharide Molecules of the Outer Membrane of Escherichia coli B from Freeze-Damage

Lipopolysaccharide (LPS) molecules of the outer membrane (OM) of Escherichia coli B were damaged by freezing and thawing as evidenced by lysozyme lysis of cells frozen in water and their inability to adsorb LPS-specific phages. Permeating cryoprotectants, i.e., glycerol and dimethylsulfoxide (DMSO), protected this damage effectively, as the frozen cells were resistant against lysis by lysozyme and were able to adsorb phages. In contrast, non-permeating cryoprotectants, i.e., polyvinylpyrrolidone (PVP) and dextran, protected LPS molecules so that frozen cells were resistant against the lytic effect of lysozyme but were not able to adsorb specific phages effectively. Although all four cryoprotectants protected cells against viability loss due to freezing, survival was much higher with glycerol and DMSO than with PVP and dextran. The non-permeating cryoprotectants likely formed a physical barrier around the cell surface, whereas the permeating cryoprotectants did not form such a barrier.

Sucrose dilution: A technique for field transfer of bovine embryos frozen in the straw

Vitrification of mammalian tissues is important in the areas of human assisted reproduction, animal reproduction, and regenerative medicine. Non-permeating cryoprotectants (CPAs), particularly sucrose, are increasingly used in conjunction with permeating CPAs for vitrification of mammalian tissues. Combining non-permeating and permeating CPAs was found to further improve post-thaw viability and functionalities of vitrified mammalian tissues, showing the potential applications of such tissues in various clinical and veterinary settings. With the rising demand for the use of non-permeating CPAs in vitrification of mammalian tissues, there is a strong need for a timely and comprehensive review on the supplemental effects of non-permeating CPAs toward vitrification outcomes of mammalian tissues. In this review, we first discuss the roles of non-permeating CPAs including sugars and high molecular weight polymers in vitrification. We then summarize the supplemental effects of non-permeating CPAs on viability and functionalities of mammalian embryos, and ovarian, testicular, articular cartilage, tracheal, and kidney tissues following vitrification. Lastly, challenges associated with the use of non-permeating CPAs in vitrification of mammalian tissues are briefly discussed.