Evaluation of post-acrosomal sheath WW domain binding protein expression in spermatozoa from infertile men with varicocele

Abstract

Background: Post-acrosomal sheath WW domain binding protein (PAWP) is one of sperm factors related to oocyte activation and is expressed in elongating spermatid. Previously, the effect of high of testicular temperature in infertile men with varicocele on semen quality, sperm DNA damage, expression of genes and proteins were reported. In this study, expression of PAWP at RNA and protein levels, and also sperm DNA damage were compared between fertile and infertile men with varicocele. Methods: In this case-control study, semen samples were collected from 35 infertile men with varicocele (grade II & III) and 20 fertile men referring to Isfahan Fertility and Infertility Center from January 2016 to September 2016. Ejaculated semen was obtained by masturbation into a sterile plastic container after 3-5 days of abstinence and was allowed to liquefy at room temperature. Briefly, sperm concentration, motility and morphology were evaluated using a sperm chamber (Sperm meter; Sperm Processor, Aurangabad, India), Computer Assisted Semen Analysis (CASA, Video Test, ltd: version Sperm 2.1, Russia) and Papanicolaou staining, respectively. In addition, DNA fragmentation, expression of PAWP at RNA and protein levels were assessed by real-time PCR, and Western blot technique, respectively. Microsoft Excel 2013 (Microsoft Corp., Redmond, WA, USA) and Package for the Social Studies were used to analyze data. We used independent-samples t-test to compare the mean value between different groups. Differences with values of P<0.05 were considered as statistically significant. Results: Mean of semen volume, sperm concentration, percentage of sperm motility, and expression of PAWP at both RNA (P=0.0001) and protein (P=0.03) levels were significantly lower in infertile men with varicocele in comparison with fertile men. In addition, mean percentage of sperm abnormal morphology and sperm DNA fragmentation were significantly higher in infertile men with varicocele in comparison with fertile men (P<0.05). Conclusion: Expression of PAWP as a protein involved in spermatogenesis and fertilization process, has decreased in infertile men with varicocele. In addition, sperm DNA integrity was disrupted in these individuals that can be considered as a main etiology of infertility