| Abstract [eng] |
Background and Rationale Female reproductive function depends on neuroendocrine regulation, ovarian follicular dynamics, and structural integrity of ovarian tissue. Chronic psychological stress contributes to reproductive dysfunction via activation of the hypothalamic–pituitary–adrenal axis and disturbance of hypothalamic–pituitary–gonadal signalling. Its direct impact on ovarian morphology is not well defined. Aim and Objectives The aim of this study was to investigate the impact of chronic psychological stress on ovarian morphology in rats. The objectives: 1. To assess the distribution of ovarian follicles across developmental stages; 2. To determine the effect of stress on follicular atresia by assessing changes in the number and size of atretic follicles; 3. To evaluate changes in the number and morphology of corpus luteum; 4. To analyze overall ovarian histomorphology, including follicle size, size of corpora lutea, and the balance between stromal and parenchymal compartments. Methods Fourteen female Wistar rats (5–7 months, 253 ± 13.1 g) were assigned to a Control group (n = 9) and a Stress group (n = 5). Chronic psychological stress was induced by daily 2 hour restraint for 28 days. After CO₂ euthanasia, ovaries were fixed in 10% neutral buffered formalin, sectioned at 4 μm, stained with hematoxylin and eosin, and analyzed with QuPath v0.5. Group differences were evaluated using the Mann–Whitney U test. Results The number of unilaminar primary follicles was higher in the Stress group than in the Control (1.366 ± 0.994 vs. 0.317 ± 0.196 per mm², p = 0.028), the only statistically significant difference. No significant differences in mean area were found for any follicle type or corpus luteum. Multilaminar primary and atretic follicles were too rare in the Stress group for meaningful comparison. Unilaminar primary follicles tended to be smaller in stressed animals (1.110 ± 321 µm²) compared with Control (1.950 ± 731 µm²), although this difference was not statistically significant (p = 0.109). Ovarian area and total parenchymal fraction tended to be lower, and stromal fraction higher, in stressed animals, but without statistical significance. Conclusions 1. Chronic restraint stress primarily affected early folliculogenesis, with an increase in unilaminar primary follicles and a decrease in primordial follicles, suggesting altered early follicular recruitment rather than uniform follicle depletion. 2. The limited number of atretic follicles in stressed animals did not allow reliable conclusions about the effects of stress on follicular atresia. 3. The number and morphology of the corpus luteum did not differ significantly between groups, indicating preserved ovulatory activity. 4. Chronic restraint stress tended to reduce the parenchymal fraction and increase the stromal fraction, indicating a shift in the stroma to parenchyma ratio without clear disruption of ovarian architecture. |
