Abstract: Abstract:Objective To discuss the role of oxidative stress (OS) and estrogen receptor (ER) levels in ectopic endome⁃ trium in patients with pelvic pain. Methods The ectopic endometrium was taken from patients with mild, moderate and se⁃ vere pelvic pain, and samples were divided into mild group (n=29), moderate group (n=34) and severe group (n=26). The nor⁃ mal samples of endometrium (n=30) were used as control group. Xanthine oxidase method was used to detect the level of su⁃ peroxide dismutase (SOD), thiobarbituric acid colorimetric method was used to detect the level of malondialdehyde (MDA) and immunohistochemistry was used to detect the level of estrogen receptor (ER). The correlation of MDA, SOD and ER lev⁃ els was analysed between three ectopic endometrium groups. Results The SOD levels were significantly lower and MDA and ER levels were significantly higher in three ectopic endometrium groups than those in control group (P <0.05). The SOD levels were decreased, while MDA and ER levels were gradually increased with increased pain intensity in three groups of ec⁃ topic endometrium (P < 0.05). There was no correlation between MDA level and ER level in mild group (P > 0.05). A posi⁃ tive correlation was found between MDA and ER levels in moderate and severe groups (P < 0.05). There was no relationship between SOD and ER levels in three ectopic endometrium groups (P > 0.05). Conclusion Over-expression of OS and ER presents in ectopic endometrium, and both participate in the occurrence of pelvic pain, and create synergies in pelvic pain of ectopic endometrium.

Key words: endometriosis, oxidative stress, receptors, estrogen, superoxide dismutase, malondialdehyde, pelvic pain