Mapping of seminal plasma proteins by two-dimensional gel electrophoresis in men with normal and impaired spermatogenesis

The present study analyses differential polypeptide expression of seminal plasma from fertile and infertile men by two-dimensional gel electrophoresis. Optimization of solubilization of seminal plasma was obtained by using [3-(3-(cholamidopropyl) dimethyl-ammonio)-1-propane sulphonate] and chaotropic agent mixture in lysis buffer before separation in immobilized pH gradient for isoelectric focusing. A two-dimensional map of seminal plasma from a fertile man allowed the detection of about 750 spots. Semi-preparative electrofocusing was performed. Analysis of tryptic fragments of two major spots by matrix-assisted laser desorption-ionization time-of-flight (MALDI-TOF) mass spectroscopy resulted in identification of prostatic acid phosphatase and prostate specific antigen. Three groups of spots and seven individual spots of isoelectric point from 4.6 to 6.2 and mol. wt from 41 to 18 kDa disappeared in the two-dimensional maps of seminal plasma of vasectomized men (n = 4) and of a patient with bilateral anorchidy as compared to that of fertile men (n = 5). Some of these polypeptides were also absent in seminal plasma of patients with alterations of seminiferous tubules showing Sertoli cell-only syndrome characteristics (n = 4) and could be potential diagnostic markers of spermatogenesis impairment.