A quick molecular method for the simultaneous detection in spermatozoa of nuclear, acrosomal and axonemal structure by fluorescent microscopy

Ejaculated spermatozoa from infertile men presenting to our laboratory for semen analysis were processed with a new molecular method which reveals simultaneously, in the same sperm cell, the status of the acrosome, by testing the hyaluronidase content, the texture of the nucleus, by checking the DNA strands breaks, and the structure of the axoneme, revealing the tubulin content. The presence of hyaluronidase and tubulin is essential for the sperm function, and the analysis of the DNA status reveals the eventual apoptotic process. Using this method in normal spermatozoa, the staining of the acrosomal hyaluronidase reveals, by yellow-green fluorescence, the shape of the acrosomal complex and its texture. At the same time, in the same sperm cell, the staining of the axonemal tubulin demonstrates, by a red labeling, the presence of the protein and therefore the consistence of the axonemal structure. Simultaneously, at the head level, the absence of red labeling from nuclear DNA indicates that the apoptotic process is not present. This protocol allows quantification of the frequency of the presence of normal or abnormal spermatozoa, by an easy scoring and calculation of the apoptotic sperm or of the sperm with generic defects at acrosomal or flagellar level. The percentage of normal spermatozoa evaluated by the triple staining method has been compared with the results of the PAP staining and of the ultrastructural analysis, statistically elaborated. Triple staining results more severe than the PAP method, but TEM analysis is the finest technique to detect sperm abnormality because it considers the entire panel of sperm defects. Human spermatozoa; Immunofluorescence; Triple staining; TUNEL