RESUMEN
Animal model studies have shown that MSY2 and JHDM2A genes have an important role in spermatogenesis process and fertility of male mice. But the potential role of these genes in human spermatogenesis and fertility is not known yet. Therefore, we evaluated expression ratios of these genes in testis tissues of men with normal and impaired spermatogenesis. In this experimental study, after RNA extraction and cDNA synthesis from 50 non-obstructive azoospermic and 12 normal testis tissues, the expression ratios of genes were evaluated by real time polymerase chain reaction [PCR] technique. Hematoxcylin and eosin [H and E] staining was used for histological classification of testis tissues. For statistical analysis, one way analysis of variance [ANOVA] test was carried out. Our results showed a significant reduction in mRNA level of YBX2 in samples with impaired spermatogenesis [p<0.001] compared to samples with qualitatively normal spermatogenesis and normal spermatogenesis; however, in JHDM2A gene, despite sensible reduction in gene expression level in men with impaired spermatogenesis, no significant differences were shown [p>0.05]. Furthermore in YBX2, a significant negative correlation was demonstrated between the efficiency score of spermatogenesis and the threshold cycle [CT] [r=-0.7, p<0.0001], whereas in JHDM2A, this negative correlation was not significant [r=-0.4, p=0.06]. Generally, these data indicated that YBX2 and JHDM2A genes may play an important role in male infertility, and suggested that these molecules can act as useful biomarkers for predicting male infertility
RESUMEN
Although aberrant protamine [PRM] ratios have been observed in infertile men, the mechanisms that implicit the uncoupling of PRM1 and PRM2 expression remain unclear. To uncover these mechanisms, in this observational study we have compared the PRM1/PRM2 mRNA ratio and mRNA contents of two regulatory factors of these genes. In this experimental study, sampling was performed by a multi-step method from 50 non-obstructive azoospermic and 12 normal men. After RNA extraction and cDNA synthesis, real-time quantitative polymerase chain reaction [RT-QPCR] was used to analyze the PRM1, PRM2, Y box binding protein 2 [YBX2] and JmjC-containing histone demethylase 2a [JHDM2A] genes in testicular biopsies of the studied samples. The PRM1/PRM2 mRNA ratio differed significantly among studied groups, namely 0.21 +/- 0.13 in azoospermic samples and -0.8 +/- 0.22 in fertile samples. The amount ofPRM2 mRNA, significantly reduced in azoospermic patients. Azoospermic men exhibited significant under expression of YBX2 gene compared to controls [P=0.001]. mRNA content of this gene showed a positive correlation with PRM mRNA ratio [R=0.6, P=0.007]. JHDM2A gene expression ratio did not show any significant difference between the studied groups [P=0.3]. We also observed no correlation between JHDM2A mRNA content and the PRM mRNA ratio [R-0.2, P=0.3]. We found significant correlation between the aberrant PRM ratio [PRM2 under expression] and lower YBX2 mRNA content in testicular biopsies of azoospermic men compared to controls, which suggested that downregulation of the YBX2 gene might be involved in PRM2 under expression. These molecules could be useful biomarkers for predicting male infertility