Withdrawal of Ovarian Steroids Stimulates Prostaglandin F2.ALPHA. Production Through Nuclear Factor-.KAPPA.B Activation via Oxygen Radicals in Human Endometrial Stromal Cells: Potential Relevance to Menstruation

Abstract

Abstract. The present study was undertaken to investigate whether withdrawal of estrogen and progesterone (EP-withdrawal) stimulates prostaglandin F2α (PGF2α) production through oxygen radical (ROS)-induced NF-κB activation in human endometrial stromal cells (ESC). To study the EPwithdrawal, ESC that had been treated with estradiol (E, 10 -8 M) and medroxyprogesterone acetate (MPA, 10 -6 M) for 12 days were then incubated with or without E+MPA for a further 11 days. PGF2α concentrations in the medium and cyclooxygenase-2 (COX-2) mRNA levels were significantly increased after EP-withdrawal, while they were unchanged by the continuous treatment with E+MPA. When ESC were incubated with N-acetyl-L-cysteine (Nac, 50 mM), an antioxidant, during EP-withdrawal, Nac blocked the increases in PGF2α production and COX-2 mRNA expression caused by EPwithdrawal. Next, we examined whether ROS generated in response to EP-withdrawal acted through NF-κB activation. Electrophoretic mobility shift assay revealed that EP-withdrawal caused marked increases in NF-κB DNA binding activity, which was completely suppressed by Nac. Furthermore, when ESC were incubated with MG132 (3 µM), which inhibits NF-κB activation, during EPwithdrawal, MG132 blocked the increases in PGF2α production and COX-2 mRNA expression caused by EP-withdrawal. In conclusion, EP-withdrawal stimulates COX-2 expression and PGF2α production through ROS-induced NF-κB activation, suggesting a possible mechanism for menstruation. Key words: Endometrial stromal cell, Prostaglandin F2α, NF-κB, Superoxide dismutase, Superoxide radical (J. Reprod. Dev. 50: [215][216][217][218][219][220][221][222][223][224][225] 2004) eactive oxygen species (ROS), including superoxide radicals, cause cell damage, whereas superoxide dismutase (SOD) is an enzyme specific to scavenging superoxide radicals and protects cells from oxygen radical cytotoxicity. Oxidative stress and its defense system have been reported to play important roles in the regulation of reproductive function [1][2][3][4][5][6][7]. In the human endometrium, SOD activities decrease and ROS levels increase in the late secretory phase, just before menstruation, suggesting that these changes in SOD and ROS may be involved in endometrial breakdown [8]. Recently, much attention has been focused on the reports that ROS act as second messengers in the regulation of cellular function [9-

Age-related Accumulation of Non-heme Ferric and Ferrous Iron in Mouse Ovarian Stroma Visualized by Sensitive Non-heme Iron Histochemistry

“…By contrast, it has been also demonstrated that ROS, including superoxide and hydrogen peroxide, play critical roles in the regulation of ovarian functions, such as oocyte maturation, folliculogenesis, ovarian steroidogenesis, and luteolysis. Thus, there is a delicate balance between ROS and antioxidant enzymes in the ovarian tissue (Shiotani et al 1991;Behrman et al 2001;Sugino et al 2004;Agarwal et al 2005;Agarwal et al 2006;Tatone et al 2008). The imbalance of ROS and antioxidants has been suggested as a mechanism of ovarian aging, as shown by decreased levels of glutathione and glutathione S-transferase in ovulated oocytes from aged mouse or downregulation of superoxide dismutase (Cu/ZnSOD and MnSOD) and catalase genes in human granulosa cells (Tarin et al 2004;Tatone et al 2006;Tatone et al 2008).…”

Effect of DHEA and metformin on corpus luteum in mice

“…The mechanisms leading to luteolysis are species specific and complex; nevertheless, PGs play an important role in its regulation. The addition of PGE to cultured ovine (Weems et al 1997), bovine (Kotwica et al 2006), human (Endo et al 1988), and rat luteal cells (Hurwitz et al 2002) increases the production of P. In contrast, the release of PGF 2a initiates luteal regression in domestic livestock (Knickerbocker et al 1988), pigs (Gadsby et al 1990), bovines (Hanselbetween PGs and the response of the antioxidant defenses in different systems is controversial (Sugino et al 2004, Al-Gubory et al 2005, Garrel et al 2007.…”

Clinical Use of Progesterone and Its Relation to Oxidative Stress in Ruminants

“…The scarce in-vivo reports studying the CL of rats and sheep have shown the importance of antioxidant enzymes in the control of CL function during the peri-implantation period. As a luteal phase defect can impact fertility by preventing implantation and early conceptus development in livestock and humans, this review attempts to address the importance of ROSscavenging antioxidant enzymes in the control of mammalian CL function and integrity [119].…”

“…The ROS include superoxide anion (dO 2 d), hydroxyl radical (dOH), nitric oxide (NO), hydrogen peroxide (H 2 O 2 ), and peroxynitrite (ONOOd). ROS are also produced via enzymatic pathways, including the activity of membrane-bound NADH and NADPH oxidases, the activity of xanthine oxidase, the metabolism of arachidonic acid by lipoxygenases and cyclooxygenases (COX), and the mitochondrial cytochrome P450 [119].…”