Cell-free seminal mRNA of DDX4 and TNP1 Genes as Potential Biomarkers of the Presence of Sperm in the Testicular Tissue

Non-obstructive azoospermia (NOA) is one of the reasons for infertility in men, and different factors including genetic factors are involved in its development. Since taking biopsies of the testicular tissue for assisted reproductive technologies (ARTs) is invasive and time-consuming, and the testicular tissue is heterogeneous, introducing a biomarker for predicting the possibility of the presence of sperm in the testicle can increase the ART efficiency. Accordingly, Cell-free seminal mRNA (CFs-mRNA), which is found in many fluids of the body including the seminal fluid of NOA individuals, can be employed as a biomarker for this purpose.

This study was conducted on 15 men suffering NOA, candidates for testicular sperm extraction (TESE), along with 15 healthy men as control. The testicular tissue of 10 patients was examined using hematoxylin and eosin staining and then classified according to Johnsen scoring. RNA was extracted from the cell-free plasma of semen samples and cDNA was synthesized. The Expression level of TNP1 and DDX4 genes was investigated using real-time polymerase chain reaction (PCR).

The expression of CFS-mRNA of the DDX4 gene was observed in only one sample of NOA individuals (10%), showing a score of 8. Further, the expression of CFS-mRNA of the TNP1 gene was observed only in two samples (20%) of NOA patients whose scores were 3 and 8.

Insufficiency or lack of expression of CFS-mRNA of TNP1 and DDX4 genes may be helpful in predicting the absence of sperm in the testicular tissue of NOA patients in terms of sperm retrieval for ART. Yet, further studies with more specific and sensitive techniques are required to achieve a more solid and precise conclusion.