During artificial insemination procedures mammalian sperm cells are particularly vulnerable to oxidative damage, which reduces the functional lifespan of sperm and consequently affects fertility. In an article in the October issue of Nature Chemical Biology, researchers report the application of a new hybrid polymer that boosts antioxidant levels in porcine sperm, enhancing both vitality and lifespan. This approach could be applied to increase fertility rates in humans or other mammals, such as rare or endangered species, in which sperm may have to be transported over long distances.
Hybrid polymers containing both antioxidant and targeting elements were designed by Benjamin Davis and colleagues to seek out the surface of mammalian sperm cells. This cell-surface interaction is mediated by a carbohydrate-binding protein that specifically recognizes galactose, a monosaccharide sugar. When the galactose-containing polymer binds to the surface of the sperm-cell, it is transported across the cell membrane, whereupon the antioxidant vitamin E is released. Treated cells had lower oxidative damage, resulting in enhanced lifespan and physiological properties. Using a fluorescence-labeled polymer, the authors were able to visualize sperm cell internalization of galactose-containing polymers. On the other hand, a galactose-free polymer was not internalized, demonstrating that polymer internalization depends on the galactose interaction with the sperm cell surface.
This work provides a viable approach for enhancing the vitality of porcine sperm. Its further application could potentially enhance fertilization rates in other mammals and provide a useful means to discover new carbohydrate-protein interactions.
Benjamin G. Davis (University of Oxford, UK)
Additional contact for comment on paper:
Eilish Donnelly (Queen's University Belfast, Northern Ireland, UK)
For abstract, click here.
(C) Nature Chemical Biology press release.
Message posted by: Trevor M. D'Souza