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 FFIgroup and the remaining 30 women belonged to MFIgroup. PON3 activity in FF of women in FFIgroup was significantly lower (p<0.05) in comparison with corresponding value in MFIgroup. The value of PON3 activity/MDA in the FFIgroup was lower than that in MFIgroup. Moreover, MDA level in the FF of FFIgroup was significantly higher (p<0.05) than its concentration in MFIgroup. 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.