title: Characterization of the paraoxonase system in follicular fluid of women subjected to an ovarian stimulation cycle.
abstract: Reactive oxygen species (ROS) and antioxidants are involved in the regulation of reproductive processes. Previous studies in infertile women undergoing an ovarian stimulation cycle have suggested a possible role for ROS in the occurrence of conception in In Vitro Fertilization. In this context the control of the redox balance of follicular fluid becomes essential for reproduction, so that the presence of enzymes with antioxidant activities, such as the paraoxonase (PON) system, would play a role in maintaining this balance. The objective of this work was a) to characterize the paraoxonase system in follicular fluid of women undergoing a controlled ovarian stimulation cycle, analysing the associated PON1, PON2, and PON3 activities, and b) to study the possible involvement of the PON system in follicular maturation. The enzyme activities were quantified in follicular fluid from large and small follicles from women undergoing an ovarian stimulation cycle in the IVI-Bilbao clinic. PON activities were quantified using spectrophotometric and HPLC techniques. Statistical comparisons were performed using the Student's t-test for paired data. Results indicate that follicular fluid presents paraoxonase activities which are detectable by the methods developed in this study. PON activities were associated with follicular maturation, suggesting that the PON system plays a role in oocyte maturation. This work was supported by research grants from the Ministry of Health and Consumption (FIS/FEDER PI11/02559), the Basque Country Government (Dep. Education, Universities and Research ref. IT687-13, and DCIT ref. S-PE13UN063), and UPV/EHU (CLUMBER UFI11/20 and PES13/58). The work was approved by the Ethics Committee of the UPV/EHU (CEISH/96/2011/RUIZLARREA), and performed according to the UPV/EHU and IVI-Bilbao agreement (Ref. 2012/01).
authors.affiliation: University of the Basque Country UPV/EHU (Medicine and Dentistry School), Department of Physiology, Spain. Electronic address: sumeijide@gmail.com.
authors.forename: Susana
authors.initials: S
authors.lastname: Meijide
authors.affiliation: University of the Basque Country UPV/EHU (Medicine and Dentistry School), Department of Physiology, Spain.
authors.forename: Irantzu
authors.initials: I
authors.lastname: Pérez-Ruiz
authors.affiliation: University of the Basque Country UPV/EHU (Medicine and Dentistry School), Department of Physiology, Spain.
authors.forename: M Luisa
authors.initials: ML
authors.lastname: Hernández
authors.affiliation: Valencian Institute of Infertility (IVI), Bilbao, Spain.
authors.forename: Marcos
authors.initials: M
authors.lastname: Ferrando
authors.affiliation: Valencian Institute of Infertility (IVI), Bilbao, Spain.
authors.forename: Zaloa
authors.initials: Z
authors.lastname: Larreategui
authors.affiliation: University of the Basque Country UPV/EHU (Medicine and Dentistry School), Department of Physiology, Spain.
authors.forename: José Ignacio
authors.initials: JI
authors.lastname: Ruiz-Sanz
authors.affiliation: University of the Basque Country UPV/EHU (Medicine and Dentistry School), Department of Physiology, Spain.
authors.forename: M Begoña
authors.initials: MB
authors.lastname: Ruiz-Larrea