Expression level of chromodomain Y (CDY): potential marker for prediction of sperm recovery in non-obstructive azoospermia

Abstract

The availability of testis specific genes will be of help in choosing the most promising biomarkers for the detection of testicular sperm retrieval in patients with non-obstructive azoospermia (NOA). Testis specific chromodomain protein Y 1 (CDY1) is a histone acetyltransferase which concentrates in the round spermatid nucleus, where histone hyperacetylation occurs and causes the replacement of histones by the sperm-specific DNA packaging proteins, TNPs and PRMs. The aim was to evaluate CDY1 gene as a marker for predicting of successful sperm retrieval in NOA patients. This research was conducted on 29 patients with NOA who had undergone testicular sperm extraction (TESE) procedure. NOA patients were subdivided into patients with successful sperm retrieval (NOA+, n=12) and patients with unsuccessful sperm retrieval (NOA-, n=17). Relative expression of CDY1 gene and chromatin incorporation of CDY1 protein were measured by quantitative real-time polymerase chain reaction (qRT-PCR) and ELISA assay, respectively. Quantification of mRNA relative expression and incorporation of CDY1 protein in chromatin showed significant lower expressions and protein levels of CDY1 in testis tissues of NOA- in comparison to NOA+ group. The findings in this study demonstrated a correlation between the low levels of CDY1 function and unsuccessful sperm recovery in the testicular tissues of NOA- compared to NOA+ patients. Therefore, it can be reasonable to consider CDY1 as a potential biomarker for predicting the presence of spermatozoa, although the claim needs more samples to be confirmed.