Oxidative stress in follicular fluid of patients submitted to controlled ovarian stimulation cycles

Abstract

OBJECTIVE: Oxidative stress is an important cause of female infertility. During follicular development, oxidative stress can induce oocyte degeneration and apoptosis, modifying the meiotic spindle and causing lipid peroxidation, loss of membrane selectivity, inactivation of cytoplasmic enzymes, and DNA damage. The aim of this study was to verify relations between concentrations of lipid peroxides (TBARS) and activity of the antioxidant enzymes glutathione peroxidase (GPx) and catalase (CAT) with the occurrence of pregnancy, hormonal stimulation protocols and presence of a female infertility factor.DESIGN: Prospective study.MATERIALS AND METHODS: Follicular fluid from 146 patients submitted to ICSI was included. Groups were divided according to pregnancy, hormonal stimulation protocol (with or without LH), and presence or not of at least one female infertility factor. Follicular fluids were collected after oocyte retrieval, and TBARS levels and CAT and GPx activity analyzed by spectrophotometry. Student's T-test or ANOVA were used, and logistic models were calculated using embryo quality on day 3, presence of female infertility, and TBARS levels and CAT and GPx activity as independent variables, occurrence of pregnancy as a binary dependent variable.RESULTS: In the non-pregnant group an increase in GPx activity (p=0,04) was observed. In the other groups no differences were observed. Logistic regression produced a model which best predicted pregnancy including presence of female infertility factor, embryo quality on day 3 and GPx activity. Odds-ratio for GPx activity was 0.990 (increasing values of GPx activity decrease the odds of occurrence of pregnancy).CONCLUSIONS: We may conclude that (i) higher GPx activity is associated to negative outcomes in ICSI cycles, (ii) inclusion of LH in ovarian stimulation protocols does not alter TBARS concentrations nor activity of antioxidant enzymes, and (iii) the presence of at least one female infertility factor does not alter TBARS levels or antioxidant activity. OBJECTIVE: Oxidative stress is an important cause of female infertility. During follicular development, oxidative stress can induce oocyte degeneration and apoptosis, modifying the meiotic spindle and causing lipid peroxidation, loss of membrane selectivity, inactivation of cytoplasmic enzymes, and DNA damage. The aim of this study was to verify relations between concentrations of lipid peroxides (TBARS) and activity of the antioxidant enzymes glutathione peroxidase (GPx) and catalase (CAT) with the occurrence of pregnancy, hormonal stimulation protocols and presence of a female infertility factor. DESIGN: Prospective study. MATERIALS AND METHODS: Follicular fluid from 146 patients submitted to ICSI was included. Groups were divided according to pregnancy, hormonal stimulation protocol (with or without LH), and presence or not of at least one female infertility factor. Follicular fluids were collected after oocyte retrieval, and TBARS levels and CAT and GPx activity analyzed by spectrophotometry. Student's T-test or ANOVA were used, and logistic models were calculated using embryo quality on day 3, presence of female infertility, and TBARS levels and CAT and GPx activity as independent variables, occurrence of pregnancy as a binary dependent variable. RESULTS: In the non-pregnant group an increase in GPx activity (p=0,04) was observed. In the other groups no differences were observed. Logistic regression produced a model which best predicted pregnancy including presence of female infertility factor, embryo quality on day 3 and GPx activity. Odds-ratio for GPx activity was 0.990 (increasing values of GPx activity decrease the odds of occurrence of pregnancy). CONCLUSIONS: We may conclude that (i) higher GPx activity is associated to negative outcomes in ICSI cycles, (ii) inclusion of LH in ovarian stimulation protocols does not alter TBARS concentrations nor activity of antioxidant enzymes, and (iii) the presence of at least one female infertility factor does not alter TBARS levels or antioxidant activity.