抄録
Many sperms use flagella to swim, and human sperm use it as well. However, the detail mechanism of the flagella movement is not clear yet. In the previous experiment, the effect of viscosity on the motion characteristics of the bovine sperm has been considered, whereas, the viscosity using in the experiment was much lower than that in the actual oviduct. The sperm should evolve to the shape that is appropriate to the environment of the actual oviduct. In this study, therefore, we conducted the observation of the sperm motion in various viscosities. We used PVP-K90 which is the Newtonian fluid, and five types of concentrations, 0.0, 1.0, 2.5, 4.0 and 6.0 [%] were selected by measuring the viscosity. The process of the experiment is the following. First, we investigated the viscosity of the reagents using a rheometer when temperature is 38.5 [℃]. Second, we centrifuged the bovine semen, and removed the seminal plasma from the semen. Third, we mixed 0.1 [ml] sperm with a buffer solution. Fourth, we observed the mixed solution with the microscope, and recorded a movie. Finally, we conducted the PTV analysis using the image analysis software (DIPP-Motion Pro, Ditect Co.), and calculated the following parameters; the straight-line velocity, the sperm velocity, and the amplitude of the sperm head. We obtained some useful results from the experimental data. First, as the viscosity increased, the motile capability of the sperm reduced. Second, as increasing in the viscosity, the sperm with no-rotating head increased, and the no-rotating sperm had lower motile capability than the rotating one. These results suggest that the sperm swim without rotating head in the actual oviduct.
