OXIDATIVE STRESS AND VASCULAR CHANGES IN THE MACULA DURING ARTERIAL HYPERTENSION

Abstract

Purpose – to evaluate changes in oxidative stress biomarkers in macular tissue and the structural–functional disturbances of the retinal microcirculation system in an experimental model of arterial hypertension.

Material and methods
The research was conducted on 65 Chinchilla rabbits at the vivarium of Azerbaijan Medical University, where a pharmacological hypertension model was induced using ergometrine maleate for 3, 5, 10, and 15 days. In homogenates prepared from the macular region, major markers of lipid peroxidation (H2O2, DC, MDA) and indicators of the antioxidant defense system (protein-SH groups, peroxidase, catalase, TAC) were measured.

Results
The results showed that oxidative stress progressively intensified in parallel with the increase in arterial pressure. From day 3 onward, the concentrations of H2O2 and DC increased noticeably, and this rise became more pronounced on days 5 and 10. By day 15, all lipid peroxidation markers – particularly DC and H2O2 – reached their maximum levels compared to the intact state. MDA levels also showed a tendency to rise throughout the model's progression.

In contrast, a gradual decline was observed in the markers of the antioxidant defense system. The levels of surface and structural protein- SH groups, as well as peroxidase and catalase, significantly decreased over time. TAC exhibited a comparatively later and milder reduction than the other markers. Overall, a direct relationship was identified between the progression of hypertension, the increase in oxidative stress, and the weakening of the antioxidant defense system.

Conclusion
The study demonstrates that sustained arterial hypertension enhances oxidative stress in macular tissue, and this process may represent one of the key pathogenic mechanisms underlying retinal microcirculatory dysfunction.