Both protamine-1 to protamine-2 mRNA ratio and Bcl2 mRNA content in testicular spermatids and ejaculated spermatozoa discriminate between fertile and infertile men

Abstract

BACKGROUND: Human sperm contain similar amounts of protamine-1 (P1) and protamine-2 (P2). Although aberrant protamine ratios have been observed in infertile men, functional evidence is provided by protamine knockout mice exhibiting male infertility. As sperm DNA integrity is known to be linked with DNA fragmentation and apoptosis, we investigated whether the protamine ratio or Bcl2 content represent a reliable biomarker to discriminate fertile and infertile men. METHODS: Real-time quantitative RT-PCR was used for P1, P2 and the apoptotic marker Bcl2 in testicular biopsies (TB; 74 infertile men versus 17 controls) and ejaculates (E; 95 infertile men versus 10 controls). RESULTS: The P1-P2 mRNA ratio differed significantly between groups, namely 1:4 versus 1:3.2 in TB (P 5 0.0038) and 1:1.7 versus 1:1 in E (P 5 0.0002), for infertile men and controls, respectively. Bcl2 mRNA content was correlated with protamine mRNA ratio (P 5 0.0250 for TB; P 5 0.0003 for E). Infertile men exhibit a more than 10-fold (P 5 0.0155 for TB; P 5 7.0 3 10 26 for E) higher Bcl2 mRNA content versus controls. No correlation was found between absolute sperm density and the protamine mRNA ratio or Bcl2 mRNA content. No significant correlation was demonstrated with fertilization rate after ICSI and either protamine ratio or Bcl2 content. CONCLUSIONS: We found significantly aberrant protamine ratios and a higher Bcl2 content in TB and E of infertile men compared to controls, suggesting that these molecules may be useful biomarkers for predicting male infertility.

NRF2 mRNA Expression in Ejaculate Spermatozoa from Men with Asthenozoospermia and Oligoasthenozoospermia

“…14,15 Therefore, the analysis of sperm mRNA profiles in ejaculated spermatozoa may be useful as a prognosis value for fertilization and a markers for predicting male infertility. 16,17 A previous study, aiming to determine the functional role of mRNA transcripts in bull spermatozoa, supports the result that sperm RNA profiling is suitable for molecular diagnosis of male gamete quality. 18 There are some studies researching the levels of different transcripts of mRNA encoding molecules containing nuclear condensation, capasity and sperm function of spermatozoa.…”

“…Also in same other studies, it has been concluded that human semen with low quality is related with abnormal sperm mRNA content for certain genes. 16,17,21 Polymorphisms in NRF2 gene were searched to insight into the relationship between defects in the NRF2 gene and human diseases. These results provided a molecular basis for the genetic analysis of the NRF2 gene and furthermore available lines of evidence show that it is worth to investigate the effect of NRF2 in other oxidative stress associated disease prognosis.…”

Low NRF2 mRNA Expression in Spermatozoa from Men with Low Sperm Motility

“…Lambard et al (2004) found that eNOS and nNOS transcripts to be undetectable in highly motile sperms, but both were present in the low motile sperms. Weidner's group also reported significantly aberrant protamine and Bcl2 mRNA expression in both testicular and ejaculated spermatozoa among infertile men (Steger et al 2008). Differences in the mRNA level of the voltagedependent anion channel (VDAC2) gene have been reported in men with low and high sperm motility (Liu et al 2010).…”

“…This suggests that NRF2 may be suitable for use as a biomarker in the prediction of ROS related male infertility. Several groups have found that low-quality human semen is associated with abnormal mRNA content for certain genes (Lambard et al 2004;Steger et al 2008;Liu et al 2010). Lambard et al (2004) found that eNOS and nNOS transcripts to be undetectable in highly motile sperms, but both were present in the low motile sperms.…”

Assessing Male Reproductive Toxicity during Drug Development

“…Histopathology studies can only be used in experimental animals [31]. Of the sperm biomarkers, the human sperm membrane protein SP22 was shown to decline after exposure to both epidydimal and testicular toxicants in rat and ram models, changes in human sperm gene expression or mRNA transcript content [24,[42][43][44]. DNA methylation profile during human spermatogenesis were correlated with impair of sperm quality (such as concentration, morphology and motility); and another specific group of sperm mRNA transcripts was shown to predict low level exposures to Sertoli cell toxicants in the rat [45][46][47].…”