Impact of protamine transcripts and their proteins on the quality and fertilization ability of sperm and the development of preimplantation embryos

Protamine 1 (PRM1) and 2 (PRM2) are major nuclear proteins in spermatozoa known to bind to chromatin during early spermatogenesis. The aim of this study was to evaluate the impact of protamine transcripts and proteins on human spermatozoa and their fertilization ability as well as the development of preimplantation embryos. Oocytes selected from 92 patients were fertilized in vitro (IVF) using their partners' sperm after evaluating its concentration, motility and morphology. Reverse transcription and real-time quantitative PCR (RQ-PCR) were applied to determine protamine mRNA level, while sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and Western blotting were used to quantify the protamine protein concentration. Next, protamine mRNA and protein levels were correlated with sperm concentration, motility and morphology as well as with the fertilization ability of mature spermatozoa and embryos of different quality obtained from the IVF program. A significant correlation has been found between protamine transcripts/proteins and: sperm concentration, progressive sperm motility, sperm fertilization ability as well as embryo quality. Protamine transcripts and proteins contribute to the quality of spermatozoa, successful fertilization and may have a significant influence on the development of preimplantation embryos. Reproductive Biology 2012 12 1: 57-72.