A study on the characteristics of excess residual cytoplasm in human spermatozoa

Abstract

Objective To observe the stability of human spermatozoa excess residual cytoplasm (ERC) in vitro and to explore the suitable detection method of ERC and its clinical significance. Methods The relationship between sperm ERC rate and time in vitro of semen, sperm motility, reactive oxygen species (ROS) and sperm maturation index levels were measured by dry and wet smear detection. Results 1) The ERC rate significantly decreased with the prolongation of spermatozoa in vitro for 0-120 min (P 0.05). However, underwent dry sperm, there were significant correlations between the ERC rate and ROS (r= 0.784, P<0.001), DNA fragment (dry staining) (r=0.574, P=0.001), HBA (r=-0.336, P=0.036), except for immature sperm nucleoprotein (dry staining). The immature sperm nucleoprotein rate of ERC spermatozoa was higher than that of non-ERC spermatozoa after drying process (P<0.001). Conclusion The ERC of spermatozoa has a tendency of progressive disintegration with the prolongation of semen in vitro. And compared with wet-smear method, the ERC retention rate of spermatozoa after natural drying (dry-smear method) has more clinical significance. The ERC level by dry-smear detection was significantly correlated with sperm motility, ROS levels and maturation. Moreover, the ERC might be a marker of poor sperm quality. Key words: Sperm; Excess residual cytoplasm (ERC); Stability; Maturation; Reactive oxygen species (ROS)