Comparative Freezing Response of Ejaculated and Epididymal Rhesus Monkey Sperm

Abstract

In the present study, we report the effects of cooling ejaculated and epididymal rhesus monkey (Macaca mulatta) sperm in the presence of extracellular. Water transport data during freezing of ejaculated and epididymal sperm cell suspensions were obtained at a cooling rate of 20 °C/min in the absence of any cryoprotective agents. Additional water transport data was obtained from ejaculated sperm at a cooling of 5 °C/min without CPAs and at 20 °C/min in the presence of 0.7M of glycerol, as well. Using previously published values, the bovine sperm cell was modeled as a cylinder of length 73.83 μm and a radius of 0.32 μm with an osmotically inactive cell volume, Vb, of 0.772Vo, where Vo is the isotonic cell volume. The subzero water transport response is analyzed to determine the variables governing the rate of water loss during cooling of bovine spermatozoa, i.e. the membrane permeability parameters (reference membrane permeability, Lpg and activation energy, ELp). The predicted best-fit permeability parameters ranged from, Lpg = 0.0023 to 0.0029 μm/min-atm and ELp = 10.6 to 45.5 kcal/mol. The subzero water transport response and consequently the subzero water transport parameters are not significantly different between the ejaculated and epididymal macaque spermatozoa under corresponding cooling conditions.