Effect of Monosaccharides in Glycerol-free Tris Extender on Reactive Oxygen Species and Apoptosis in Dog Sperm Cryopreservation.

BACKGROUND OBJECTIVE

The present study investigated the effect of monosaccharides in a glycerol-free tris (GFT) extender on reactive oxygen species (ROS) levels and apoptosis in cryopreserved dog spermatozoa.

MATERIALS AND METHODS

The sperm pellets were resuspended (5 × 10 mL) with GFT containing 172 mM glucose (G), 86 mM glucose + 86 mM fructose (GF), 86 mM glucose + 86 mM galactose (Gg), 172 mM fructose (F), 172 mM galactose (g) or 86 mM fructose + 86 mM galactose (Fg). The sperm (500 µL) were loaded in 0.5 mL straws and cooled for 50 min at 4 degree C. The straws were then frozen 7 cm from the surface of liquid nitrogen (LN2) for 20 min and were finally plunged into LN2. After freezing-thawing, the sperm motility and viability were evaluated. The ROS level (HO) and apoptosis index were assessed by using flow cytometry.

RESULTS

GFT supplemented with GF resulted in significantly higher (P < 0.05) progressive sperm motility and viability followed by only G, which had greater ROS reducing capacity. However, sperm cell apoptosis had no significant differences among all the experimental groups.

CONCLUSION

Cryopreservation of dog sperm in GFT containing GF yields more motile and viable sperm followed by only G, which has greater ROS reducing efficiency.