Comparing antioxidant enzyme levels in follicular fluid in ICSI-treated patients

Oxidant-antioxidant imbalance has an adverse effect on all stages of reproduction. Follicular fluid levels of superoxide dismutase (SOD) and catalase, and the rate of embryo development were compared in women at early perimenopausal and childbearing age, undergoing intracytoplasmic sperm injection (ICSI).

Patients (n=168) were divided: 110 women at childbearing age (27-35), and 58 aged 40-46. SOD and catalase levels were determined using spectrophotometry, and embryo culture assessed every 10 minutes.

Statistically significant differences were observed between the number of pregnancies at child-bearing age (30.91%) and early perimenopause (3.45%) (Chi(2)=15.417, df=1, P=0.0001); also between the rate of embryo development from pronuclear to 4-cell stage, and to achievement of blastocyst stage. This rate was faster in women at childbearing age than those older. SOD levels were lower in younger than older women (Z=-8.473, P<0.001). Catalase levels were significantly higher in patients at childbearing age than those aged 40-46 (Z=-8.473, P<0.001). On the basis of the Kruskal-Wallis test, the group of younger patients showed the occurrence of a statistically significant correlation between the class of embryos, assessed on the second day of observation, and SOD concentration, in which class A showed a mean of 31.83 U/mL, whereas SOD for the B class was -27.61 (H=9.380, P=0.009). During the inner cell mass (ICM) and trophectoderm (TE) assessments in both groups, higher mean SOD concentration accompanied the highest quality of embryos, but statistically significant correlations concerned only older patients in the case of ICM (H=8.476, P=0.014) and TE (H=8.251, P=0.016).

The rate of embryo development decreases with age. In early perimenopause, SOD levels increase, while catalase levels decrease. Additionally, in early perimenopause, SOD activity shortens the time in which 4-cell stage is achieved, while catalase activity delays the 5-cell and blastocyst stages. The quality of embryos has no association with catalase concentration. SOD concentration is associated with the good quality of embryo on the second day of development. The quality of blastocyst in patients in the early perimenopausal age is dependent on SOD concentration. However, the most important prognostic factor of pregnancy after ICSI is age.