Sperm mitochondrial dysfunction and oxidative stress as possible reasons for isolated asthenozoospermia.

Reduced sperm motility, defined as asthenozoospermia, is a frequent cause of male infertility, and is mainly connected with the dysfunction of sperm mitochondria. The aim of this study was to identify the proteins, and thereby the metabolic pathways, responsible for asthenozoospermia, using 2-DE and MALDI-TOF MS, and correlate the results obtained with those of two mitochondrial tests: JC-1 and MitoSox Red. The JC-1 test was performed to test sperm mitochondrial activity, and the MitoSox Red test was performed to check whether the observed sperm poor motility is associated with mitochondrial reactive oxygen species (ROS) production. To identify proteins strictly connected with reduced sperm motility, men with isolated asthenozoospermia (n = 4 versus 10 normozoospermic controls) alone were included in the study. The proteomic analyses resulted in the identification of 25 sperm proteins that are differentially expressed in asthenozoospermic individuals. Most of the identified proteins were downregulated and were involved in energy production; however, we have also identified structural sperm proteins and proteins secreted by the epididymis. The latter, together with the results from MitoSox Red assay, may provide insights into the pathophysiological basis of asthenozoospermia.

Proteomic identification of sperm antigens using serum samples from individuals with and without antisperm antibodies.

The aim of the study was to identify human sperm antigens reacting with polyclonal antisperm antibodies. Protein sperm extracts were subjected to electrofocusing, and next immune reactions (immunoblotting) were carried out with positive for antisperm antibodies and control (not containing antisperm antibodies) serum samples. Proteomic analysis of human sperm proteins resulted in identification of 80 sperm antigens that could be divided into three groups: antigens specific for patients with antisperm antibodies (32), antigens recognised by both infertile patients and control sera (35) and antigens detected by control serum samples only (13). Among antigens specific for infertile patients, there were 12 sperm entities known to be involved in fertilisation process. We have also characterised three protein entities identified only by sera of infertile women. Altogether, the proteomic analysis resulted in identification of 27 sperm entities not reported previously in human sperm proteome. Identified proteins are sperm antigens that could be potentially responsible for immunological infertility. The study also sheds new light on the sperm antigens in aspect of gender specificity. The investigation of human sperm proteome by the use of antisperm antibodies-containing sera of infertile individuals not only may indicate new proteins but also can draft their immunological nature.