Human Reproduction 2010 25(5):1251-1258

Seok Kyo Seo¹, Hyo In Yang², Kyung Eun Lee², Hye Yeon Kim¹, SiHyun Cho¹, Young Sik Choi² and Byung Seok Lee^1,*

¹ Department of Obstetrics and Gynecology, Gangnam Severance Hospital, Yonsei University, College of Medicine, 146-92 Dogok-dong, Gangnam-gu, Seoul 135-720, Korea ² Department of Obstetrics and Gynecology, Severance Hospital, Yonsei University, College of Medicine, 250 Seongsanno, Seodaemun-gu, Seoul 120-752, Korea

^* Correspondence address. Tel: +82-2-2019-3435; Fax: +82-2-3462-8209; E-mail: dr222@yuhs.ac

BACKGROUND: Oxidative stress is considered to be involved in the establishment and development of endometriosis. Thioredoxin (TRX) is an endogenous redox regulator that protects cells against oxidative stress, and TRX-binding protein-2 (TBP-2) is a negative regulator of TRX in the biological function and expression. The aim of this study was to investigate the roles of TRX and TBP-2 in the pathophysiology of endometriosis.

METHODS: A total of 35 patients with histologically confirmed endometriosis and 31 patients without endometriosis participated in this study. Real-time polymerase chain reaction was used to quantify TRX and TBP-2 mRNA levels, and immunohistochemistry (IHC) was used to assess TRX and TBP-2 protein localization in the endometrium. Serum and peritoneal fluid levels of TRX and TBP-2 were measured using a specific commercial ELISA.

RESULTS: There were no significant differences in TRX mRNA levels in the endometrium of patients with endometriosis and the control groups. However, TBP-2 mRNA levels in the endometrium were lower, and the TRX to TBP-2 ratio was higher in patients with endometriosis than in the control group. In particular, the TRX to TBP-2 ratio was significantly higher during late secretory and menstrual phase in patients with endometriosis compared with the control group. IHC studies also showed the decreased TBP-2 immunoreactivity in patients with endometriosis compared with the control group. There was no correlation between TRX and TBP-2 mRNA levels in patients with endometriosis, whereas TRX mRNA levels were positively correlated with TBP-2 mRNA levels in the control group. There were no significant differences between the two groups in TRX and TBP-2 levels in serum or peritoneal fluid.

CONCLUSIONS: Aberrant expression of TRX and TBP-2 in the endometrium may be associated with the establishment of endometriosis.

Key words: oxidative stress/endometriosis/thioredoxin/thioredoxin-binding protein-2