Expression of selected sperm microRNAs in teratozoospermia and globozoospermia and their association with sperm motility and intracytoplasmic sperm injection outcomes: A cross-sectional study

Background: MicroRNAs (miRNAs) are small non-coding RNAs that regulate gene expression after transcription. Therefore, changes in miRNA levels can interfere with post-transcriptional gene regulation and are linked to various disease conditions, including male infertility. Objective: This study aimed to assess the expression levels of sperm miRNAs in globozoospermia and teratozoospermia, compare them with those in normozoospermic men, and explore the relationship between miRNA levels, sperm parameters, and intracytoplasmic sperm injection outcomes. Materials and Methods: In this cross-sectional study, a total of 59 semen samples (14 globozoospermic, 20 teratozoospermic, and 25 normozoospermic) were collected. Sperm were separated from seminal plasma for the assessment of DNA fragmentation, DNA oxidation, protamine deficiency, and the expression of 9 miRNAs (namely miR-15a-5p, miR-10a-5p, miR-26b-5p, miR-34c-5p, miR-149-5p, let-7a-5p, miR-320b-3p, miR-296-3p, and miR-191-5p) using reverse transcription-quantitative polymerase chain reaction. The relationships between fertilization rate, embryo quality score, and the evaluated sperm parameters were analyzed following intracytoplasmic sperm injection. Results: Among the miRNAs examined, miR-191 demonstrated significantly elevated expression levels in globozoospermic samples relative to normozoospermic controls (p = 0.03). Within the normozoospermic cohort, miR-15a-5p, miR-10a-5p, and miR-320b exhibited positive correlations with sperm motility (p = 0.03, p = 0.02, p = 0.04, respectively). Similarly, in the globozoospermic cohort, all miRNAs except miR-34c showed positive correlations with motility. The findings also revealed increased DNA oxidation in both teratozoospermia and globozoospermia samples compared to the normozoospermia group (p < 0.001). Conclusion: Although the examined sperm miRNAs did not exhibit significant correlations with morphology or fertilization rate, significant associations between several miRNAs and sperm motility were observed in specific study groups, particularly among globozoospermic men.