Differential Expression of VASA Gene in Ejaculated Spermatozoa from Normozoospermic Men and Patients with Oligozoospermia

Aim: To detect the expression of VASA in human ejaculated spermatozoa, and to compare the expression of VASA between normozoospermic men and patients with oligozoospermia.

Methods: Ejaculated spermatozoa were collected from normozoospermic men and patients with oligozoospermia by masturbation, and subsequently segregated through a discontinuous gradient of Percoll to obtain the spermatozoa. Reverse transcription polymerase chain reaction (RT-PCR), quantitative RT-PCR (QRT-PCR), immunoflurescence and Western blotting were used to detect the expression of VASA in mRNA and protein levels.

Results: VASA mRNA was expressed in the ejaculated spermatozoa. QRT-PCR analysis showed that VASA mRNA level was approximately 5-fold higher in normozoospermic men than that in oligozoospermic men. Immunofluorescence and Western blotting analysis showed that VASA protein was located on the cytoplasmic membrane of heads and tails of spermatozoa, and its expression was significantly decreased in oligozoospermic men, which is similar to the result of QRT-PCR.

Conclusion: The expression of VASA mRNA and protein was significantly decreased in the sperm of oligozoospermic men, which suggested the lower expression of the VASA gene might be associated with pathogenesis in some subtypes of male infertility and VASA could be used as a molecular marker for the diagnosis of male infertility.