Testicular expression of TDRD1, TDRD5, TDRD9 and TDRD12 in azoospermia

Background

Tudor domain-containing proteins (TDRDs) play a critical role in piRNA biogenesis and germ cell development. piRNAs, small regulatory RNAs, act by silencing of transposons during germline development and it has recently been shown in animal model studies that defects in TDRD genes can lead to sterility in males.

Methods

Here we evaluate gene and protein expression levels of four key TDRDs (TDRD1, TDRD5, TDRD9 and TDRD12) in testicular biopsy samples obtained from men with obstructive azoospermia (OA, n = 29), as controls, and various types of non-obstructive azoospermia containing hypospermatogenesis (HP, 28), maturation arrest (MA, n = 30), and Sertoli cell-only syndrome (SCOS, n = 32) as cases. One-way ANOVA test followed by Dunnett’s multiple comparison post-test was used to determine inter-group differences in TDRD gene expression among cases and controls.

Results

The results showed very low expression of TDRD genes in SCOS specimens. Also, the expression of TDRD1 and TDRD9 genes were lower in MA samples compared to OA samples. The expression of TDRD5 significantly reduced in SCOS, MA and HP specimens than the OA specimens. Indeed, TDRD12 exhibited a very low expression in HP specimens in comparison to OA specimens. All these results were confirmed by Western blot technique.

Conclusion

TDRDs could be very important in male infertility, which should be express in certain stages of spermatogenesis.

Detection of Y Chromosome Microdeletions and Hormonal Profile Analysis of Infertile Men undergoing Assisted Reproductive Technologies

Background

Y chromosome deletions (YCDs) in azoospermia factor (AZF) region are associated with ab- normal spermatogenesis and may lead to azoospermia or severe oligozoospermia. Assisted reproductive tech- nologies (ART) by intracytoplasmic sperm injection (ICSI) and testicular sperm extraction (TESE) are com- monly required for infertility management of patients carrying YCDs. The aim of this study was to estimate the frequency of YCDs, to find the most frequent variant in infertile men candidate for ART and to compare YCD distribution with a control fertile group. The semen parameters, hormonal profiles and ART outcomes of the infertile group were studied.

Materials and Methods

This case-control study consisted of 97 oligozoospermic or non-obstructive azoospermic (NOA) infertile men, who had undergone ART, as the case group and 100 fertile men as the control group. DNA samples were extracted from blood samples taken from all 197 participants and YCDs were identified by multiplex polymerase chain reaction (PCR) of eight known sequence-tagged sites. The chi-square test was used to compare the mean values of hormone and sperm parameters between the two groups. P<0.05 was considered statistically significant.

Results

No YCD was detected in the control group. However, 20 out of 97 (20.6%) infertile men had a YCD. AZFc, AZFbc and AZFabc deletions were detected in 15 (75%), four (20%) and one (5%) YCD-positive patients. No fer- tilization or clinical pregnancy was seen following ICSI in this sub-group with YCD. The mean level of FSH was significantly higher in the group with YCD (28.45 ± 22.2 vs. 4.8 ± 3.17 and 10.83 ± 7.23 in YCD-negative patients with and without clinical pregnancy respectively).

Conclusion

YCD is frequent among NOA men and YCD screening before ART and patient counseling is thus strongly recommended.