The transcriptional factor Sox2 regulates the expression of some of the de-velopmental genes, which are essential for the maintenance of pluripotency of stem cells. Sox2 also expresses in the female gamete during folliculogenesis, but its role remains am-biguous. The aim of this study was to investigate the expression of Sox2 in the mice ovarian tissue during different stage of estrous cycle. Adult National Medical Research Institute (NMRI) mice were considered as pro-estrous, estrous, met-estrous and di-estrous based on the cell type of the vaginal smear. Immunohistochemical staining of Sox2 marker was per-formed in mice ovarian tissue. Immunohistochemical staining revealed the expression of Sox2 in the cytoplasm of corpus luteum cells, stromal cells and oocyte. Our results suggest that adult mice ovaries accommodate cells carrying stem cell features.

Reproductive cycle in rodents is known as estrous cycle. In rodents, the duration of the estrous cycle is shorter than other mammals. The shortened estrous cycle made rodents as a suitable animal model to evaluate the impact of drug treatment, nutritional effect, and stress on reproductive cycle. In bread mouse like BALB/c showed significant decrease in case of reproductive efficiency. The aim of the present study was to find simple and reliable method for detection of different stages of estrous cycle in rodents, especially in mice. One of the proposed methods in estrous cycle monitoring would be the conventional vaginal sampling. In the present study, this method has been modified. To conduct the study we use 10 mice. Mice had ad libitum accessed to water and food. The light cycle was 12: 12 (L/D). All the samples were collected between 9-11 A.M. Sampling was performed using 100 mL sampler and physiological slain solution. Results of the present study revealed that a combination of three different cell types were detectable during Pro-estrous (nuclear epithelial cells, cornified epithelial cells), Estrous (cornified epithelial cells), Met-estrous (cornified epithelial cells, and leucocytes), and Di-estrous (leucocytes).

Methomyl is an oxime carbamate pesticide that is widely used in the Philippines. This insecticide is known to be an endocrine disrupting chemical and a potent genotoxic in mammalian cells. However, limited studies were conducted specifically on its direct effects on estrous cycle and its teratogenic effect. This study aimed to (a) assess the effect of methomyl on the body weight and on the estrous cycle of mice, and; (b) examine the teratogenic effect of methomyl on the progeny of the female albino mice. Five week-old experimental mice in three treatment setups were used in the study for both independent experiments. The treatment schedule for pregnant mice was administered during organogenesis (day 6 to 15 of gestation). Results showed that the average gained weight of the mice of both high dose (HD) and low dose (LD) groups were lower as compared to the average gained weight of the control group but did not show any statistical significant differences (p=0. 562). For the experiment 1, methomyl significantly (p=0. 013) affect the estrous cycle of the mouse especially in LD group. For experiment 2, results revealed that there was a significant difference among the treatment set-ups (p=0. 0001) in terms of fetal morphometric measurement. Furthermore, abnormality and high number of resorption was also observed in both LD and HD treatment groups. Therefore, methomyl significantly affect the body weight, estrous cycle and fetal morphometry. This further confirm that methomyl is an endocrine disrupting and genotoxic chemical that affects the estrous cycle and causes teratogenic effect.

Background: Sex differences in the morphology and function of the hippocampus have been reported in several species. Natural fluctuations of sex hormones during the estrous cycle affect the hippocampal neurogenesis of adult female. This study aimed to investigate the neurogenic changes in the hippocampus at different phases of estrous cycle.Materials and Methods: Different stages of the estrous cycle of the NMRI mice (6-8) mice were determined by staining of vaginal smears. Also, the qualitative assessment of cell proliferation in the dentate gyrus of hippocampus was performed by Nissl staining and Ki-67 immunostaining marker (Ki-67). The apoptosis was determined using the TUNEL assay. Diameter of the hippocampal vessels was measured at different stages of the estrous cycle.Results: In microscopic sections stained with Cresyl Violet observed cell density in proestrous stage of estrous cycle was greater than any other stages of the estrous cycle. Comparison of sections stained with immunohistochemistry for Ki-67 staining showed that cell proliferation at proestrous are more than any other stages. The statistical analysis showed that vessel diameter was significantly greater at the proestrous stage than diestrous and metestrous. Also, TUNEL assay showed that cell death in the proestrous stage had the least reactivity.Conclusion: Proestrous stage of the estrous cycle was associated with increased cell proliferation and vessel diameter as well as reduced cell death in the dentate gyrus of the mice hippocampus.