Proteomic analysis of seminal plasma in adolescents with and without varicocele

Abstract

Varicocele is the leading treatable cause of male infertility. This study aims to compare the proteomic profile of seminal plasma of adolescents with varicocele and alteration in seminal quality, adolescents with varicocele and normal semen and adolescents without varicocele. A transversal study. One hundred and fifty six adolescents were initially evaluated from a school from São Paulo and 67 adolescents were recruited for the study. The adolescents were divided into three groups: Control group (without varicocele and normal seminal analysis) with 21 individuals, normal semen varicocele group (NSV) with 28 individuals and altered sperm varicocele group (ASV) with 18 individuals. Two semen samples of each adolescent with one week interval between them were obtained and analyzed according to World Health Organization criteria of 1999 and sperm morphology by Kruger. The seminal plasma proteomic profile initially was analyzed by two-dimensional electrophoresis, and the final proteins of interest were identified by mass spectrometry and bioinformatics database. The data were analyzed by ANOVA test and a LSD (post hoc) test. Two specific proteins for apoptosis (SMG1_HUMAN and IBP3_HUMAN) were found exclusively in ASV group. The NSV group was the only to show the BRE1B_HUMAN, a protein related to spermatogenesis. The control group detected the greater number of proteins related to sperm motility (SEMG1_HUMAN, SEMG2_HUMAN, KLK3_HUMAN) and sperm capacitation (PPAP_HUMAN, LRMP_HUMAN and NPC2_HUMAN). Clinical varicocele with or without seminal alterations cause alterations in the protein profile of seminal plasma. The differences between the protein expressions in seminal plasma of adolescents with and without varicocele should be studied for better understanding of their functions, promoting the acquisition of early biomarkers of damage to sperm function.