PERIODIZATION OF ADAPTATION-COMPENSATORY REMODELING OF BRAIN STRUCTURES IN INCOMPLETE PERMANENT CEREBRAL HYPOPERFUSION IN RATS

Abstract

Bilateral one-stage ligation of the common carotid arteries in rats is the most common way to form prolonged cerebral hypoxia with cognitive impairment. Early postoperative periods, up to 3 x days, are most commonly used for pharmacological studies. They are characterized by neuronal death, development of hypoenergetic state and edema. In the acute period - 3-8 days, the changes are associated with the activation of astrocytes, which form intercellular cooperation between the neuron, hemocapillary and respiratory burst of neutrophil granulocytes. The permeability of the blood-brain barrier increases. This is accompanied by death of one part of neurons and improvement of vitality of another part. The subacute period from 8 days to 8 weeks is accompanied by death of neurons in a state of poor life support, activation of microglia, myelin fibers damage, increase in the diameter of paravertebral arteries - in the early period, and the development of astrocytosis and angiogenesis - in the late period, which leads to the growth of lipid peroxidation, secondary damage and neuronal death. In the late period, neurodystrophic changes appear, minor neuronal apoptosis and increased permeability of the blood-brain barrier persist. The surviving neurons show metabolic activation and concentration of pericarions near the hemocapillaries.