A significantly different transcriptome is found between sperm samples from patients undergoing homologous intrauterine insemination (IUI) achieving or not pregnancy

Abstract

OBJECTIVE: Sperm analysis is deficient in predictive power on pregnancy achievement in IUI, mainly because the lack of information regarding the molecular causes of these failure attempts. New tools are being introduced to improve sperm analysis. Massive testing equipments such as microarrays are interesting options to be employed in assisted reproduction. Our aim with this work is to use microarray technology to characterize differential gene expression profiles between sperm samples achieving or not pregnancy in IUI cycles.DESIGN: Cases and controls study with 20 sperm samples obtained from infertile males undergoing their first IUI cycle presenting normal sperm count and motility (WHO criteria) parameters, having their partners normal infertility work-up investigation results. After freezing aliquots of the sperm samples employed for IUI from patients accomplishing the inclusion criteria, we identified samples from which pregnancy was achieved (P, n=10) or not (NP, n=10).MATERIALS AND METHODS: Sperm mRNA was extracted using Trizol protocol, suspended in DEPC-treated water and frozen at −80°C until the microarray experiments were performed. RNAs were analyzed on Agilent Bioanalyzer 2100. The results were evaluated with the Gene Ontology that describe gene products in terms of their associated biological processes in different steps (www.geneontology.org) and those genes differentially expressed (GDE) at least twice, with statistically significant differences between P and NP sperm samples.RESULTS: 872 GDE were found in group P, presenting increased expression, whereas 204 were found in group NP. In group P 3.4% of the GDE presented fold changes (FC) >10, 16.3% with FC between 5 and 10, and 80.3% have a FC <5. In group P, 222 genes (31.2% of GDE in group P) are involved in cell communication and 209 (29.4%) are signal transduction genes, among other functions. In NP group only 2 genes have FC ≥5, 99% of them presented FC <5. From them, 39 genes (25.5% of GDE in group NP) are involved in multicellular organic processes and 35 in developmental processes (22.9%). There are no complete biological processes statistically affected.CONCLUSIONS: To our knowledge, this is the first work describing profound differences in the expression profiles between samples which achieved pregnancy vs. those unable in assisted reproduction. These differences could be potentially employed to detect IUI success markers, although it needs to be further explored in order to figure out their biological roles. OBJECTIVE: Sperm analysis is deficient in predictive power on pregnancy achievement in IUI, mainly because the lack of information regarding the molecular causes of these failure attempts. New tools are being introduced to improve sperm analysis. Massive testing equipments such as microarrays are interesting options to be employed in assisted reproduction. Our aim with this work is to use microarray technology to characterize differential gene expression profiles between sperm samples achieving or not pregnancy in IUI cycles. DESIGN: Cases and controls study with 20 sperm samples obtained from infertile males undergoing their first IUI cycle presenting normal sperm count and motility (WHO criteria) parameters, having their partners normal infertility work-up investigation results. After freezing aliquots of the sperm samples employed for IUI from patients accomplishing the inclusion criteria, we identified samples from which pregnancy was achieved (P, n=10) or not (NP, n=10). MATERIALS AND METHODS: Sperm mRNA was extracted using Trizol protocol, suspended in DEPC-treated water and frozen at −80°C until the microarray experiments were performed. RNAs were analyzed on Agilent Bioanalyzer 2100. The results were evaluated with the Gene Ontology that describe gene products in terms of their associated biological processes in different steps (www.geneontology.org) and those genes differentially expressed (GDE) at least twice, with statistically significant differences between P and NP sperm samples. RESULTS: 872 GDE were found in group P, presenting increased expression, whereas 204 were found in group NP. In group P 3.4% of the GDE presented fold changes (FC) >10, 16.3% with FC between 5 and 10, and 80.3% have a FC <5. In group P, 222 genes (31.2% of GDE in group P) are involved in cell communication and 209 (29.4%) are signal transduction genes, among other functions. In NP group only 2 genes have FC ≥5, 99% of them presented FC <5. From them, 39 genes (25.5% of GDE in group NP) are involved in multicellular organic processes and 35 in developmental processes (22.9%). There are no complete biological processes statistically affected. CONCLUSIONS: To our knowledge, this is the first work describing profound differences in the expression profiles between samples which achieved pregnancy vs. those unable in assisted reproduction. These differences could be potentially employed to detect IUI success markers, although it needs to be further explored in order to figure out their biological roles.