Differential seminal plasma proteome according to semen retrieval in men with spinal cord injury

Abstract

Objective: To evaluate protein expression profile and to quantify proteins present in seminal plasma from men with spinal cord injury (SCI) and healthy men without SCI.

Design: Experimental study.

Setting: University hospital.

Patient(s): Twelve SCI patients divided into two groups, six who underwent electroejaculation (EEJ) and six who underwent penile vibratory stimulation (PVS); and ten control subjects presenting normal sperm motility and concentration.

Intervention(s): EEJ and PVS.

Main outcome measure(s): The seminal plasma protein profile was analyzed by two proteomic strategies: data-independent label-free quantitative proteomics (MS(E)) and two-dimensional sodium dodecyl sulfate-polyacrylamide gel electrophoresis (2D SDS-PAGE).

Result(s): A total of 638 different proteins were identified by MS(E) and 18 by 2D SDS-PAGE followed by tandem mass spectrometry. Interactome analysis showed key reproductive biologic processes-insemination, sperm and oocyte fusion, and acrosome reaction-related to all groups, as were triglyceride stimuli. Processes related to actin and muscle function and to iron oxidation, transportation, and homeostasis were found only in the EEJ and PVS groups; response to hydrogen peroxide and increased immune response was found only in the PVS group.

Conclusion(s): This study was able to demonstrate differential protein expression among control, PVS, and EEJ groups; SCI is responsible for alterations in seminal plasma protein profile leading to a deviation from homeostasis; proteins reported in both PVS and EEJ groups correlate with the pathophysiology of SCI-related infertility.

Keywords: Biomarkers; functional enrichment; proteomics; seminal plasma; spinal cord injury.