Paraoxonase 3 Activity and The Ratio of Antioxidant to Peroxidation in The Follicular Fluid of Infertile Women

BACKGROUND Paraoxonase-3 (PON3), as a high density lipoprotein (HDL)-associated lactonase, is capable of preventing the oxidative modification of low density lipoprotein (LDL). PON3 activity in follicular fluid (FF) is three times more than its activity in serum. However, the detailed role of PON3 in women's fertility remains unknown. The aim of this study was to investigate the correlation between PON3 activity in the FF of women undergoing assisted reproductive technique (ART), in vitro fertilization (IVF), or intra-cytoplasmic sperm injection (ICSI). MATERIALS AND METHODS This cross-sectional study consisted of 50 women from couples with male factor infertility (MFI) or with female factor infertility (FFI). The FF samples were obtained during the ART intervention. PON3 activity, HDL cholesterol (HDL C), total antioxidant status (TAS) and the level of malondialdehyde (MDA) were determined. The morphology of the embryo was determined using embryo cell number (ECN) and embryo fragmentation score (EFS). In addition, fertilization rate (FR) was used an oocyte fertilization index. RESULTS Of 50 women, 20 women belonged to FFI group and the remaining 30 women belonged to MFI group. PON3 activity in FF of women in FFI group was significantly lower (p<0.05) in comparison with corresponding value in MFI group. The value of PON3 activity/MDA in the FFI group was lower than that in MFI group. Moreover, MDA level in the FF of FFI group was significantly higher (p<0.05) than its concentration in MFI group. Meanwhile, no significant difference was found in HDL-C concentration and TAS of both groups. No significant correlation was observed between the ECN and FF biochemical parameters. There was also a negative correlation between FR and MDA (r=-0.42, p=0.02), whereas a positive relation between FR with PON3 activity (r=0.59, p=0.004), HDL-C (r=0.35, p=0.04) and PON3/MDA (r=0.59, p=0.001). CONCLUSION According to the results of this study, PON3 activity level as a key component of antioxidant system in FF may directly be associated with the success rate of ART and fertilization rate in women.