Quantification of sperm specific mRNA transcripts (PRM1, PRM2, and TNP2) in teratozoospermia and normozoospermia: New correlations between mRNA content and morphology of sperm.

Sperm mRNAs could be used as a predictor of fertilization capacity since the transcriptional profile of a gamete is critical for the production of viable human sperm. The aim of this study was to determine if PRM1, PRM2, and TNP2 transcripts in spermatozoa from normozoospermic and teratozoospermic men correlate with sperm morphology and/or assisted-reproduction outcomes. Human ejaculates were collected from 138 men referred to an infertility clinic, and were separated in two groups, teratozoospermic (n =72) and normozoospermic (n =66), based on World Health Organization criteria (2010). Chromomycin A3 and analine blue staining were used to evaluate protamination and chromatin integrity, respectively. Quantitative reverse-transcriptase PCR was performed for PRM1, PRM2, and TNP2. This analysis revealed significantly higher PRM1 and PRM2 mRNA copy numbers in normozoospermic versus teratozoospermic samples (P < 0.001). In contrast, TNP2 transcript abundance was significantly higher in teratozoospermic versus normozoospermic samples (P < 0.001) and positively correlated with sperm-head defects (P < 0.05). Sperm-tail defects negatively correlated (P < 0.05) with both PRM1 and PRM2 transcripts in normozoospermic samples. No significant differences were observed between the two groups when comparing transcript levels to the outcome of intracytoplasmic sperm injection cycles (P > 0.05), and a normal PRM1/PRM2 mRNA ratio (∼1) was observed in more than 70% of successful cycles. Thus, the quantity of PRM1, PRM2, and TNP2 transcripts and the PRM1/PRM2 mRNA ratio affect spermiogenesis, sperm morphology, and the function of mature human sperm. These mRNAs could therefore be used as biomarkers for the diagnosis of male infertility.