Identification of human spermatogenesis-related proteins by comparative proteomic analysis: a preliminary study.

Objective: To identify human spermatogenesis-related proteins.

Design: Prospective study.

Setting: University research laboratory.

Patient(s): Three fertile men with normal spermatogenesis, 3 azoospermic patients with sloughing and disorganization of germ cells.

Intervention(s): Testicular tissue samples were collected by biopsy after informed consent.

Main Outcome Measure(s): The protein expressional profiles of human testes of fertile men and azoospermic patients were compared using a proteomic approach by combining two-dimensional gel electrophoresis analyses and mass spectrometry. Bioinformatic analysis helped to reveal the regulation pathway. Expression of some selected proteins in normal and pathological testes was analyzed by immunohistochemistry.

Result(s): Ten protein spots were identified as expressing differentially between the normal testes and pathological testes with sloughing and disorganization of germ cells; these included the phospholipid hydroperoxide glutathione peroxidase, peroxiredoxin 4 (Prx4), heat shock protein beta-1 (HSP27), and cathepsin D (CTSD). Bioinformatic analysis revealed that many differentially expressed proteins participate in cellular proliferation, apoptosis, and cell death and helped us to focus on a few of them. Immunohistochemical analysis of Prx4, HSP27, and CTSD confirmed the results obtained by proteomic analysis.

Conclusion(s): These 10 proteins may help in elucidating the pathways involved in human spermatogenesis.