The Preliminary Proteomic Study Of Seminal Plasma In Varicocele

Objective: To compare seminal protein samples from infertile male caused by VC and normal fertile man using isobaric tags for relative and absolute quantification(i TRAQ) labeling technique coupled to 2D LC–MS/MS analysis and to explore the possible molecular basis of male infertility caused by VC.Method: 10 semen samples from infertile man caused by left side VC(grade II or III)and 10 from normal fertile man were collected as experimental and control group respectively. The seminal protein samples were labeled with i TRAQ reagents(117 for infertile group and 114 for control group) then submit to 2D LC–MS/MS analysis. The MS data was analyzed by Proteome Discoverer1.3 software and 1.3 fold-change of the up regulated or down regulated proteins, P≤0.05, was considered there were statistically significant difference. All the obtained proteins were conducted in bioinformatics analysis.Results: a total of 1100 proteins were recognized and 89 proteins were differential expressed when compared with control group, of which 45 up regulated and 44 down regulated. GO enrichment analysis showed that the biological precess of the proteins were response to wounding defense response, inflammatory response, acute inflammatory response, acute-phase response.3 preteins zona pellucida-binding protein 1 isoform 2 precursor, phosphoglycerate kinase 2(PGK2), semenogelin-1 preproprotein were related to spermiogenesis and reproduction.Conclusion: The effects of varicocele on male fertility could be reflected by the change of differentially expressed proteins in seminal. Those complex biological processes(wounding defense response, inflammatory response)may lead to declines of male fertility. However, the specific molecular mechanism is unclear. We selected 3 reproductive related proteins may served as biomarker of male infertility, further study is needed to verify those proteins. i TRAQ technique could apply to the study of male infertility and lay the foundation for understanding the molecular mechanisms of male fertility caused by varicocele.