The role of stress-related neuroendocrine mechanisms in the progression of experimental glaucoma

Abstract

Glaucoma is a progressive neurodegenerative disease and one of the leading causes of irreversible blindness, in which elevated intraocular pressure (IOP) and vascular dysfunction contribute to optic nerve damage. Chronic stress-associated conditions with activation of the hypothalamic–pituitary–adrenal axis may affect disease progression through neuroendocrine mechanism. Military-relevant stress (MRS), characterized by high intensity and elevated corticosterone (CORT) levels, may affect physiological processes, although its role in glaucoma progression remains insufficiently studied. Aims: The aim of this study was to evaluate the effect of MRS on the course of adrenaline-induced glaucoma (AIG) in rats, taking into account changes in IOP, systemic stress response, and vascular alterations. Methods: Animals were divided into 4 groups: control, AIG, and AIG+MRS. Experimental glaucoma was induced to produce sustained IOP elevation, while MRS was modeled by combined acoustic, light, and mechanical stressors. IOP and blood CORT levels were measured over time were assessed at the end of the experiment. Repeated measures ANOVA, Bonferroni-corrected post hoc tests, and correlation analysis were performed, with statistical significance set at p≤0.05. Results: Analysis of variance demonstrated statistically significant changes in both CORT levels and IOP over time. For CORT, significant effects of time (F(2,64) = 236.8), group (F(2,32) = 5.07), and time × group interaction (F(4,64) = 54.02) were observed. For IOP, significant effects of time (F(2,62) = 67.17), group (F(2,31) = 30.60), and their interaction (F(4,62) = 19.48) were also identified. Post hoc analysis showed differences between all time points for both parameters. No intergroup differences were found at baseline, whereas significant differences appeared on days 21 and 42. For CORT, the main difference was observed between the AIG+MRS and control groups. For IOP, all groups differed, with the greatest changes in the AIG group. Correlation analysis showed no association between CORT levels and IOP on day 21 (r = −0.174; ρ = −0.248), while a positive correlation was found on day 42 (r = 0.369; ρ = 0.524). Conclusions: CORT levels and IOP demonstrated statistically significant changes over time depending on the group. Their positive association at a later stage suggests a potential role of stress-related neuroendocrine mechanisms in the progression of experimental glaucoma.