Research On Spermatozoal Proteins In Patients With Asthenozoospermia

Infertility is a major medical and social problem throughout the world. It is estimated that approximately 10%～20% of human couples are affected by infertility, and about half of these cases can be attributed to the male partner. Male factor infertility is a general term that describes a situation in which the inability to conceive is present with an alteration identified in the male partner. This dysfunction may be associated with poor sperm motility(asthenozoospermia), low sperm concentration (oligozoospermia), or abnormal sperm morphology (teratozoospermia). In general, asthenozoospermia, is the most common phenomenon in male subfertility and infertility. Although spermatic motility is important for normal fertility, elementary research on the spermatozoal proteins or protein functions is relatively sparse. Proteomics and protemic techniques are among the most valuable approaches in the research of life science in this new century, analyzing proteins efficiently in a large scale using biochemical and molecular biological methods. Its introduction into the exploration of spermatozoal protein expression changes and their relationship with male infertility has given us so many pleasant surprises.The current study focused on the comparative research of differentially expressed spermatozoal protein profiles in patients with idiopathic asthenozoospermia and normozoospermic donors using proteomic techniques. At the same time, we also tried to find special proteins involved in the regulation of spermatic motility. We collected 90 sperm samples from patients with asthenozoospermia, which were divided into three groups (moderate group, n=30; medium group, n=30; severe group, n=30) according to characteristics of spermatic activity, and another 30 from fertile men with normal spermiograms as a control group. All the patients underwent medical history, clinical examination and CASA. Then we extracted the proteins, ran SDS-PAGE electrophoresis and stained the gels. After that, the differential expression proteins were analyzed. DDX4, which is the VASA Homo sapiens homolog protein was detected on spermatozoa of both fertile and abnormal groups by Western Blotting technique, which is a classical route to identify unknown proteins. A statistically significant difference was shown between donors with normal spermiograms and patients with asthenozoospermia (P＜0.05). Decreased expression of DDX4 was observed in patients with pathological spermiograms. The differential expression profile of DDX4 in normal and asthenozoospermia groups implied that it was closely associated with fertility and infertility. Our findings suggested that DDX4 played an important role in the sperm function, or might serve as a highly specific biochemical marker in the evaluation of spermatic motility.In summary, our data identified one protein expressed differentially in poor motility sperm samples compared with normal sperm samples by proteomic approaches. For one thing, the conclusions will provide new ways in the research on the molecular mechanismic of spermatic motility and male fertility regulation. For another, the research will also be useful in supplying systematic and detailed protocals for the screening, isolation and identification of differentially expressed spermatozoal proteins. Finally, our work may contribute a useful guidance in searching new therapeutic targets possibly in the diagnosis and treatment of male infertility with asthenozoospermia.