Background and Aim: Estrogen affects the metabolism in females. This study aimed to assess the effect of absence of estrogen on orthodontic tooth movement in rats. Materials and Methods: In this animal study, 55 rats were randomly divided into four groups. Group 1 (n=10) had intact ovaries. In group 2 (n=15), ovaries were intact but the rats were subjected to stress due to tooth preparation. In group 3 (n=15), the ovaries were intact but the rats were subjected to stress due to tooth preparation and surgical manipulation. In group 4 (n=15), ovaries were removed and the rats were subjected to stress due to tooth preparation and surgical manipulation. Orthodontic appliances were placed after 14 days in groups 2 to 4. All groups except for group 1 were subjected to mesial movement of maxillary right first molar using NiTi closed coil spring applying 60g load for 21 days. The rats were sacrificed at 21 days and the amount of orthodontic tooth movement was measured using a feeler gauge. Data were analyzed using ANOVA. Results: The mean orthodontic tooth movement was 1. 18± 0. 2 mm in group 4, which was significantly greater than that in group 3 (0. 47± 0. 18 mm) and group 2 (0. 22± 0. 07 mm) (P<0. 001). Conclusion: Absence of estrogen can significantly accelerate orthodontic tooth movement in rats.

Asthma is a chronic inflammation of the airways affecting over 300 million people worldwide. As in the autoimmune diseases, it is well described that women are the most affected by asthma. The higher number of women presenting this pathology suggests the involvement of female sex hormones in the construction of the allergic immune response. Female Balb/c mice were used for the experiments. Thirty-eight animals were separated into four groups: OVX-Ova; Sham-Ova; OVX-Sal; Sham-Sal. Then animals underwent acute allergic induction protocol by Ovalbulmin (OVA). Ovariectomized animals showed greater number of leukocytes in bronchoalveolar lavage (BAL) and elevated white blood cells recruitment to the lung environment observed by histological analysis. There was a significant increase of eosinophils and mast cells in inflammatory sites at pulmonary tissue. The relative uterine and body weight were lower in ovariectomized animals and higher in Sham mice, respectively. Moreover, the lack of the sex hormones induced an increase in interleukin (IL)-4 and titers of immunoglobulin G1 (IgG1) antibodies. However, increased production of IL-17A was only observed in Sham animals. Altogether, data this study suggest that ovariectomy induces the formation of a stronger Th2 response in allergic animal. However, the immune processes involved in the allergic response in females currently remain unclear.

Background: The harmful impact of ovariectomy on myocardial ischemia-reperfusion (M/IR) injury has been established in the short term. Objectives: In this study, we aimed to investigate the long-term effects of ovariectomy on M/IR injury. Methods: Twomethods involving dorsolateral skin incisions were used to induce the ovariectomized (OVX) rat model. The rats were divided into 2 groups: Control and OVX (n = 6). At the end of the study, the hearts were isolated and subjected to global ischemia using the Langendorff apparatus. Cardiac function indices (CFIs) were recorded, including left ventricular end-diastolic pressure (LVEDP), peak rates of positive (+dp/dt) and negative (-dp/dt) changes in LV pressure, and LV-developed pressure (LVDP). At the end of the reperfusion period, the hearts were used to measure the size of the infarct, levels of nitric oxide metabolites (NOx), andmRNA expression of NO synthase (NOS) enzymes, including endothelial (eNOS), neuronal (nNOS), and inducible (iNOS). Results: Compared to controls, OVX rats had larger infarct size by 51%, higher LVEDP by 29%, and lower recovery of +dp/dt, –, dp/dt, and LVDP by 29%, 22%, and 35%, respectively. Furthermore, in heart tissue, rats that underwent OVX had significantly higher concentrations of nitrate, nitrite, and NOx by 79%, 82%, and 83%, respectively. Additionally, these rats had lower mRNA levels of eNOS by 38% and higher mRNA levels of iNOS by 71%. Conclusions: The long-term deficiency of estrogen increased the expression of iNOS and decreased the expression of eNOS in the heart tissue of OVX rats. Imbalanced NOS expressions were associated with exacerbated responses to M/IR injury in OVX rats.