Oxidative stress markers in preovulatory follicular fluid in humans

Intensified peroxidation in the Graafian follicle may be a factor compromising the normal development of the oocyte. The aim of this study was to measure concentrations of three oxidative stress markers: conjugated dienes, lipid hydroperoxides and thiobarbituric acid-reactive substances, in preovulatory follicular fluids and sera of 145 women attending an in-vitro fertilization programme, and to correlate these concentrations with pregnancy outcome. Determinations were conducted either with or without an antioxidant (10 mu M butylated hydroxytoluene) and an iron chelate (10 mu M deferoxamine mesylate) to examine peroxidation associated with the methods used. Concentrations of conjugated dienes, lipid hydroperoxides and thiobarbituric acid-reactive substances in follicular fluid were all significantly lower than those in serum, both in the presence or absence of the antioxidant and iron chelate. These concentrations did not correlate with pregnancy outcome. In conclusion, the intensity of peroxidation in the Graafian follicle is much lower than that in serum. This gradient is the result of the lower rate of initiation of peroxidation in the follicular fluid, suggestive of the presence of efficient antioxidant defence systems in the direct milieu of the oocyte before ovulation. The concentrations of investigated oxidative stress markers in follicular fluid do not reflect the reproductive potential of oocytes.