Bull sperm rheotaxis and kinematics in microfluidic channels with different heights

Abstract

Recently, microfluidics has attracted a lot of attention in reproduction due to its ability to simulate the natural environment inside the female reproductive tract and its ability to separate high-quality sperm cells using rheotaxis as a selection mechanism. Positive rheotaxis refers to the ability of the sperm to direct itself and swim against the liquid current during the fertilization journey. In this study, we investigated the effects of various microchannel heights on sperm positive rheotaxis (PR) and sperm kinematics. We used two microchannels with the same width (200µm) and different heights (channel 1= 20 µm height and channel 2= 100 µm height). Sperm samples were obtained from two bulls with known fertility and analyzed using CASA. The results showed that PR and all sperm kinematics (VCL, VSL, VAP