1C43 非ニュートン流体が精子運動特性に与える影響に関する数値解析

抄録

Infertility is often cited as one of the causes of the declining birthrate, which has a social problem in recent years. Roughly 10% of couples have infertility problems, and almost 50% of all cases of infertility are associated with a lack of sperm or sperm abnormalities. Therefore, motile sperm are required to increase the probability of fertilization. We previously observed of flagellar motion of bovine sperm and clarified that ambient fluid viscosity and non-Newtonian properties affected its shape and motion. However, the detail mechanics of the effect of surrounding fluid properties on the sperm motion is still unclear. Therefore, we simulated the sperm motion in various viscosity and non-Newtonian fluid to reveal the effect of the surrounding environments on the sperm motility. The simulation results indicated the decrease in the sperm velocity when the viscosity increased, because the increase in the viscosity lead to increase in the resistance of the ambient fluid. Additionally, the increase in the viscosity brought about the increase in sperm motility. We compared the present results with previous experimental data for the sperm velocity, and estimated the sperm motility for each viscosity. Consequently, we obtained the relationship of viscosity coefficient and sperm motility. These results will provide the useful information to estimate the sperm motility for various fluid properties.