P-230: Analysis of TEX15 Expression in Testis Tissues of Severe Oligozoospermic and Non-Obstructive Azoospermic Men Referred to Royan Institute

Background: TEX15 is a novel protein that is required for chromosomal synapsis and meiotic recombination. Human TEX15 is located on chromosome 8(8p12 region) and expressed in testis and ovary, as is its mouse ortholog. Loss of TEX15 function in mice causes early meiotic arrest in males but not in females. Specifically, TEX15 deficient spermatocytes exhibit a failure in chromosomal synapsis. In Tex15 -/- mutant spermatocytes, DNA double-strand breaks (DSBs) are formed, but localization of the recombination proteins to meiotic chromosomes is severely impaired. These results indicate that TEX15 regulates the loading of DNA repair proteins onto sites of DSBs and thus its absence causes a failure in meiotic recombination. Materials and Methods: The samples retrieved from patients who underwent diagnostic testicular biopsy in Royan institute. 10 patients with severe oligozoospermia and 10 patients with non-obstructive azoospermia (with SCOS syndrome) were recruited. Total RNA was extracted with Trizol reagent and cDNA was synthesized. Quantitative real-time RT-PCR for TEX15 was performed using Power SYBR Green kit. Results: Normalizing the relative amount of TEX15 transcript by the amount of GAPDH transcript in the same sample, indicated that expression of TEX15 in the testis samples of patients with nonobstructive azoospermia(SCOS patients) is significantly reduced as compared with oligozoospermic patients (p value=0.0009). Conclusion: The same expression pattern and sequences homology of TEX15 among mouse and human indicated that TEX15 is a highly conserved gene that might have an important role in mammalian testis functions like spermatogenesis. Although its function in human is unknown, its role in mouse is spermatogenesis.It can be concluded that TEX15 can also have the same role in human. According to the results, we can conclude that TEX15 expression levels are essential for normal spermatogenesis and deficiency in this gene can cause spermatogenic failure and infertility in men.