Human RNAs as potential biomarkers for sperm quality and male infertility.

Reliable molecular biomarkers to predict fertility remain scarce. The current study explored the potential of testis-specific RNAs as biomarkers for male infertility and sperm quality. Using RT-PCR and RT-qPCR assays, we identified seven circular RNAs from the human gene in human sperm. We found that sperm RNA exhibited a significantly decreased expression in asthenozoospermia while and expression decreased in teratozoospermia, compared with the controls. Furthermore, expression exhibited a negative correlation with sperm DNA Fragmentation Index (DFI), and levels were correlated with both fertilization and cleavage rates involving assisted reproductive technologies. Further functional analyses in a transgenic fly model lent support for the roles of RNAs in sperm development and human fertility. Collectively, our findings support that sperm RNAs may serve as diagnostic biomarkers for assessing sperm motility and DNA quality. Hence clinical application and significance of sperm circular RNAs in assisted reproductive technologies warrant further investigation.