RESUMO
Objective: Endometrial hyperplasia (EH) is considered an endometrial cancer precursor. This study aimed to determine the role of oxidative stress and thiol groups with antioxidant properties in EH pathogenesis. Materials and Methods: In our prospective case-control study, participants were washed with 5 mL of saline before the endometrial biopsy. Endometrial washing fluid was taken into microtubules, and thiol and disulfide levels were analyzed using the Ellman reagent. Results: A total of 108 patients were in the EH group and 84 patients in the control group. The total and native thiol levels were higher values in the control group (p<0.001, for both). Disulfide levels were higher in the EH group (p<0.001). Native/total thiol ratio and disulfide/total thiol ratio were higher in the EH group (p<0.001, for both). The analysis performed in the control group revealed a significant positive correlation between estradiol and disulfide levels (r=0.322, p=0.033). No significant correlation was found between estradiol and disulfide in the EH group. Conclusion: Oxidative stress level was higher in the washing fluids of patients with EH and this stress plays a role in the EH etiology.