Unexpected in vitro fertilization failure in patients with normal sperm: A proteomic analysis

Objective. - Despite normal sperm parameters, 5% of in vitro fertilization (IVF) attempts result in an unpredictable failure of fertilization. In 56% of the cases, there is no obvious oocyte anomaly, but lack of sperm binding to the zona pellucida. This study aims to contribute to clarify the male molecular causes of failures in IVF, which are undetected by classical sperm analysis. Patients and methods. - The spermatic proteomic profiles of patients, with a complete failure of fertilization and no spermatozoa bound to the zona pellucida, is compared to controls (patients with normal fertilization and cleavage rates after a classical IVF for tubal indication). All samples are analysed by 2 Dimensional Electrophoresis-Differential In Get Electrophoresis (2DE-DIGE) after being divided into three fractions according to their isoelectric point (acid, intermediate and basic). Results. - Fourteen proteins differentially expressed between all the cases and all the controls were highlighted. Twelve of these proteins were identified by mass spectrometry (six from the acid fraction and six from the basic fraction). Two of these proteins may have an interest in gametic interaction: the laminin receptor LR67 and the L-xylulose reductase. Discussion and conclusion. - More investigation is needed to understand the involvement of the identified proteins in the IVF fertilization failure of the infertile patients in this study. (C) 2009 Published by Elsevier Masson SAS.