Abstract
<b><i>Introduction:</i></b> The objective of this study was to investigate the relationship between the activity of neutral α-glucosidase in seminal plasma and semen quality and to explore the effect of secretory capability of the epididymis on male fertility. <b><i>Methods:</i></b> A retrospective analysis of 542 men treated in the Center for Reproductive Medicine and Infertility from February to December 2022, the semen parameters and neutral α-glucosidase were tested and compared among different groups. These 542 men included normozoospermia, oligospermia, asthenospermia, and teratozoospermia. <b><i>Results:</i></b> There was statistical difference in neutral alpha-glucosidase (NAG) level among different groups with different sperm concentration, motility, and morphology (<i>p</i> < 0.001). The NAG activity in seminal plasma was positively correlated with ejaculate volume and sperm concentration; meanwhile, a very weak positive correlation was found between NAG level and sperm motility, sperm morphology, respectively. <b><i>Conclusions:</i></b> Our results indicated that the secretion of NAG affected the volume, concentration, motility, and morphology of sperm to a certain extent. Given that NAG is a specific and marker enzyme in epididymis, where is the site of sperm maturation, we can conclude that there is a close relationship between NAG and sperm quality. Therefore, seminal plasma NAG has a definite clinical value in helping diagnosis of male infertility.