RESUMO
The experiment on 20 male Wistar rats has demonstrated that under light exposure 3 500 lux for 7 days on different-aged rats morphological changes are observed in the II, IV and V layers of the primary visual cortex. They manifest itself as percentage increase of reversibly and irreversibly altered neurons, mainly in the fourth layer in 18-month-old rats (p≤0,05). Thus, under light exposure in 18-month-old rats the percentage of hyperchromic wrinkled neurons runs up to to 6% (5; 8,5) and the percentage of neurons with total chromatolysis increases up to 10% (8,5; 14) in comparison with 1% (0,5; 14) and 6% (5; 8) in 3 month rats under light exposure, respectively (p≤0,05). The neural damage leads to the glial reaction, which is expressed by the percentage increase of glia with edema and swelling signs, hyperchromia without shrinkage of the nucleus and cytoplasm (p≤0,05), neuronophagy, and the intrusion of gliocytes into the neuron cytoplasm for initiation of intracellular repair. The destructive changes are characterized by hyperchromia of gliocytes with shrinkage of the nucleus and cytoplasm. The percentage of such gliocytes significantly increases in the IV layer in 18 month old rats under light exposure, in comparison with the indexes of young animals (p≤0,05).
