Oxidative Stress and Ovarian Function

Different levels of ROS were detected in the follicular fluid environment that may interfere with folliculogenesis and steroidogenesis [139, 140]. Folliculogenesis refers to the maturation of the ovarian follicle, a densely packed shell of somatic cells that contains an immature oocyte. The production of cytokines, kinins, prosta-glandins, proteolytic enzymes, nitric oxide, and steroids before last stage of oocyte production enhances the flow of blood to the ovary [141]. Low intrafollicular oxygenation due to poor blood flow to follicles reduces the developmental potential of oocytes [142].

Physiologically, normal development of the oocyte (ovulation) and the subsequent embryo may require certain levels of ROS in follicular fluid [7]. Follicular fluid may contain leukocytes, macrophages, and cytokines, which can all produce ROS [7]. Oxidative stress found to affect the midluteal corpus luteum and steroidogenic capacity both in vitro and in vivo. The presence of ROS in the follicular fluid environment surrounding the oocytes may play a critical role in fertilization and embryo development, influencing IVF outcome parameters such as fertilization, embryo cleavage, and pregnancy rates [ 5] . Some studies reported a correlation between follicular growths and programmed follicular cell death with nitric oxide (NO) concentration; at a low level, may prevent apoptosis, while at high concentration it may promote cell death by peroxynitrite generation [143]. LPO seen in the preovulatory Graafian follicle suggests an important role of oxidative stress in ovarian function [144].

On the other hand, the presence of lower concentrations of ROS in follicular fluid than that in serum indicate to the presence of high concentrations of antioxidant systems in follicular fluid which help protect an oocyte from oxidative damage [144].

Superoxide dismutase (SOD), an antioxidant enzyme, was found in the ovary, particularly in the theca interna cells in the antral follicles protectes the cells from harmful free radicals of oxygen [145] . Therefore, theca interna cells may act as important protectors of the oocyte from OS during oocyte maturation. In another study, it was found that glutathione peroxidase may reduce levels of hydroperoxides inside follicle [146].

Other antioxidant enzymes such as catalase and other nonenzymatic antioxidants such as vitamin E, ascorbic acid, reduced glutathione, and the carotenoid lutein have been suggested to protect the oocyte and the embryo from OS by detoxifying and neutralizing ROS production [7].

Pregnancy Guide

Pregnancy Guide

A Beginner's Guide to Healthy Pregnancy. If you suspect, or know, that you are pregnant, we ho pe you have already visited your doctor. Presuming that you have confirmed your suspicions and that this is your first child, or that you wish to take better care of yourself d uring pregnancy than you did during your other pregnancies; you have come to the right place.

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