P-141: Impact of Oxidative Stress Induced with BSO on Development and Dif-ferentiation of Ovarian Follicles in Mice

Background: Whenever the balance between Antioxidants and reactive oxygen species (ROS) is disrupted towards an overabundance of ROS, oxidative stress (OS) occurs. There is evidence that glutathione as an intracellular antioxidant plays an important role against ROS in female reproductive system. BSO is a selective inhibitor of glutathione peroxidas. The aim of the present study is to investigate BSO induced OS effect on development and differentiation of ovarian follicles in mice. Materials and Methods: In this study, 30 female and 15 male mice were used. The female mice were divided into 3 groups of control, sham and experimental ones.Two female mice at their stereos cycle were put with one male mouse in a cage for mating. Observation of vaginal plaque was considered as the first day of pregnancy and the mice on 13th day of pregnancy received 2 mmol/ kg BSO daily until delivery as IP injection. After the pregnancy the 2, 3, 6 and 7 days old new born were sacrificed and their ovaries were prepared for light and electron microscopic studies. The number of follicular nests and diameter of primordial and primary follicles were determined using Motic software and compared with control values. Results: Light microscopy and morphometry showed that follicular nests are distinguished on the 2nd and 3rd days old newborn and follicles on 6th and 7th days. Morphometric studies revealed that the number of follicular nests were similar in control and sham groups, but significantly (p<0.001) reduced in experimental groups in comparison to control group. However, the number and diameters of primordial and primary follicles in experimental and controls were not significantly different. TEM showed that cytoplasmic organelles in experimental group had preapoptotic features. Conclusion: The result indicates that oxidative stress suppresses follicular differentiation at early stages but does not affect the development of already differentiate follicles.