The Expression And Role Of Oxidative Stress Markers In The Serum And Follicular Fluid Of Patients With Endometriosis

BackgroundEndometriosis is a common, estrogen dependent, chronic gynecological disorder associated with pelvic pain and infertility. Endometriosis is considered a benign disease but shares some features with cancer, such as propensity to invasion, unrestrained growth, neoangiogenesis, and distant spreading. Studies estimate that endometriosis may affect around 25% women of reproductive age, and the prevalence of infertility in these women ranges from 21% to 44 %,and 4%-22% infertile woman have endometriosis. To date, there are no ideal treatments for endometriosis and endometriosis-associated infertility, which associated with uncertain pathogenesis of the endometriosis related to infertility. A number of studies on endometriosis have been done, but the researchers and the clinical doctors still can not completely illuminate it. The widespread development of the assisted reproductive techniques (ART) brings the new hope for the endometriosis-associated infertility patients. Simultaneously, it is possible to study the mechanism of infertility caused by endometriosis from different aspects. Most studies suggest that the success of the endometriosis-associated infertility with ART was 50% lower than that the tubal factor infertility. This outcome is contributed to the detrimental effect of the endometriosis on the oocyte quality ,the fertilizability of the sperm and oocyte, the quality of the embryo and the implanted environment of the embryo. In order to improve the success of the endometriosis-associated infertility with IVF-ET, it is very important to explore the mechanism of infertility caused by endometriosis from different decks. In recent years, more and more researchers pay attention on the role of oxidative stress in endometriosis. There is an increasing number of diseases associated with oxidative stress. Therefore, the correlation between oxidative stress and endometriosis-associated infertility has become a worldwide research.ObjectiveTo assess the level of ROS, SOD, VE in the serum and follicular fluid of patients with endometriosis, and combine the clinical index to estimate the effect of oxidative stress on the outcome of the patients with endometriosis who were submitted to IVF-ET. Investigate the mechanism of endometriosis-associated infertility.MethodsA prospective case-control study was conducted on 42 patients who were submitted to ovulation induction for IVF-ET. These patients were divided into the study group(20 patients with endometriosis) and the control group(22 patients with tubal factor infertility). All patients underwent a long GnRH agonist protocol for pituitary downregulation followed by controlled ovarian hyperstimulation. Peripheral blood and follicular-fluid samples were collected on the day of oocyte retrieval. Reactive oxygen species(ROS), superoxide dismutase(SOD) and vitamin E(VE) were measured by enzyme linked immunosorbent assay (ELISA). Compare the outcome of IVF-ET between the two groups: include retrieved oocytes, mature oocyte rates, fertilization rates, good-embryo rates, implantation rates and clinical pregnancy rates, and analysis the correlation between the levels of above oxidative stress markers and the outcome of IVF-ET. Results1. The levels of ROS in serum of the study group were significantly higher than the control group, SOD and VE levels in serum were significantly lower in the study group(P<0.05). ROS levels in follicular fluid were significantly higher in the study group(P<0.05), whereas no significant difference in SOD and VE levels in follicular fluid was observed between groups(P>0.05). In addition, ROS,SOD and VE levels were found to be significantly lower in follicular fluid than in serum in both groups(P<0.05).2. The mature oocyte rates and fertilization rates were significantly lower in the study group compared with the control group. There was no significant difference in retrieved oocytes, good-embryo rates, implantation rates and clinical pregnancy rates in both groups. But the good-embryo rates, implantation rates and clinical pregnancy rates in study groups were slightly lower than the control group3. The levels of ROS, SOD and VE in serum and follicular fluid were not significant correlated with the IVF-ET outcome index(P>0.05). But we also found ROS levels in serum and follicular fluid have the tendency of inverse correlation with mature oocyte rates and fertilization rates; SOD levels in serum and follicular fluid have the tendency of positive correlation with mature oocyte rates, fertilization rates, implantation rates and clinical pregnancy rates; VE levels in serum and follicular fluid have the tendency of positive correlation with mature oocyte rates, fertilization rates, good-embryo rates, implantation rates and clinical pregnancy rates.ConclusionsThe levels of ROS in serum and follicular fluid were significantly higher in the study group, and a significantly decrease in antioxidant was observed in the same group. It proves that the patients with endometriosis have the oxidative stress exactly. The group of patients with endometriosis not only presented increased ROS in follicular fluid but also maintained lower SOD and VE levels than the control group, We speculate that there is detrimental effect on the oocyte quality caused by oxidative stress, which leads to lower mature oocyte rates and fertilization rates in endometriotic patients. Whether ROS, SOD and VE could be the predict markers of IVF-ET outcome in endometriotic patients or not, we need further research.