Chemotactic responses of spermatozoa to progesterone gradients.

<p>(A) An overview of concentration gradients generated in the hexagon. Progesterone solution was added in every other channel of the chip (red). Concentration gradients were generated in three regions in the hexagon corresponding to peripheral channels where progesterone solution was loaded. Blue square showed the field where sperm chemotaxis were observed. (B) A microscopic photograph of spermatozoa with several trajectories indicated (18 sperm). Each colored line represented a sperm trajectory within 3 s. (C-E) Comparisons of chemotactic parameters among three groups. Group A, 100 pM progesterone solution was added in peripheral channels; Group B, 1 mM progesterone solution was added; Group C, control. Data are presented as mean ± SD (n = 5). **: <i>p</i> < 0.05.