Acrosome intactness and seminal hyaluronidase activity: relationship with conventional seminal parameters

Seminal hyaluronidase activity was estimated after liquefaction in semen samples of 100 male partners of infertile couples including 16 azoospermic (no spermatozoon) men and 48 fertility proven men by a method based on measurement of the area of digestion of substrate (hyaluronic acid) in agar plate. Semen samples were also evaluated for Acrosomal Intactness (AI) test except the azoospermics of the studied samples. Seminal hyaluronidase activity was completely absent in azoospermic specimens confirming its cellular origin. Seminal hyaluronidase activity was found to be significantly correlated, statistically, with sperm density (r = 0.708, p < 0.001), % motility (r = 0.6478, p < 0.001) and % normal sperm morphology (r = 0.5724, p < 0.001). Acrosomal Intactness (AI) test scores were also well correlated with sperm density (r = 0.6477, p < 0.001), % motility (r = 0.5965, p < 0.001) and % normal morphology (r = 0.6237, p < 0.001). Both values were higher in semen samples with normal routine parameters (proven fertility and normozoospermic infertile groups) than those compared with abnormal routine parameters (oligozoospermic). We also found very highly significant correlation (r = 0.8442) between seminal hyaluronidase activity and Acrosomal Intactness scores, statistically (p < 0.001). This could be because; normal germinal semineferous epithelium generates abundant number of sperms with normal motility and morphology that are also having intact acrosome. Intact acrosome prevents loss of acrosomal enzymatic activity (e.g. hyaluronidase) until released after liquefaction during seminal analysis and during acrosomal reaction in female genital tract prior to fertilization. Seminal hyaluronidase activity, thus determined, is primarily dependent upon the intact status of acrosome. As each sperm contributes to the seminal hyaluronidase activity, it is directly correlated with sperm density; but at the same time it exhibits goods correlation with % motility and % normal morphology. Therefore AI score and seminal hyaluronidase activity can be considered as good indicators of sperm function.