IMPACT OF PATHOGENIC FACTORS ON STRUCTURAL AND FUNCTIONAL CHANGES IN THE RAT BRAIN

Abstract

Environmental pollution, particularly by heavy metals, represents one of the key factors contributing to contemporary public health risks. The impact of such toxic substances on the human body is systemic in nature and manifests at various levels of biological organization. In this context, the investigation of adaptive and compensatory mechanisms becomes especially relevant under conditions of exposure to diverse environmental pollutants. In this study, the functional state of rat brain tissue was assessed by analyzing the formation of a food-conditioned reflex in a T-shaped maze over a 10-day period. In the control group, a gradual reduction in maze completion time and error frequency was observed, indicating normal learning processes. In contrast, rats exposed to peroxidized oil, aluminum chloride intoxication, or combined pathological factors demonstrated significantly impaired learning performance. The most pronounced cognitive deficits were recorded in animals subjected to combined toxic exposure. Biochemical analysis of brain homogenates revealed a statistically significant increase in the activity of acid phosphatase and elastase in the experimental groups, indicating the development of an inflammatory response and disruption of the blood-brain barrier. The presence of urease activity in the brain tissue of rats with toxic damage confirms microbial colonization and the neurotoxic effects of ammonia. Elevated levels of malondialdehyde (MDA) across all experimental groups suggest activation of lipid peroxidation and the onset of intoxication. Increased catalase activity reflects a compensatory response of the antioxidant defense system. Histological examination confirmed the presence of pericellular and perivascular edema, lymphoid infiltration, necrotic foci, and cystic changes, particularly in rats exposed to aluminum and combined pathology. These findings indicate the development of neurodegenerative alterations, microcirculatory disturbances, and immune activation. The rat model of toxic brain injury offers promising opportunities for further investigation into the mechanisms of neurotoxicity and the development of preventive strategies.