Tracking Sperm Flagellum Waveform

The mouse caudal epididymis was removed and bluntly dissociated in 1 mL high-saline solution (HS: 135 mM NaCl, 5 mM KCl, 1 mM MgSO₄, 2 mM CaCl₂, 20 mM HEPES, 5 mM glucose, 10 mM lactic acid and 1 mM Na-pyruvate, adjusted to pH 7.4 with NaOH) to release the sperm at 37 °C for 10 min. Then, the sperm suspension was transferred to petri dishes coated with 0.05% polylysine in advance, so that the sperm head was fixed, while the tail could swing freely. The flagellum oscillation of sperm was recorded at 200 fps for 3 s and multiple images were generated using a Hamamatsu digital camera C13440 (Hamamatsu, Tokyo, Japan) equipped in a Nikon microscope. Fuji software was used to synthesize a superimposed image to track the waveform of the sperm flagellum, as previously represented [48 (link)].