The nNOS and NeuN expression aspects in the cerebral cortex of rats with different cognitive abilities in cerebral hypoperfusion with short-term physical exercise

Abstract

Introduction. Physical activity is often used in rehabilitation to restore cognitive function after cerebral blood flow impairment and typological features like baseline cognitive ability may alter their effectiveness.The aim was to evaluate the expression of nNOS and NeuN in the large hemisphere cortex in the cerebral hypoperfusion occurrence in rats having different scores in the Morris maze.Materials and methods. Cerebral hypoperfusion was simulated by bilateral ligation of the common carotid arteries. Before surgery, Wistar rats were divided into equal subgroups with high (HCA) and low levels of cognitive ability (LCA) according to the results of Morris maze testing. Animals were removed from the experiment at 8, 21, 35, 60, and 90 days after surgery, a total of 184 rats, 24 formed the control group and 80 formed the cerebral hypoperfusion subgroup with 80 animals undergoing short-term swimming daily starting on day 7 of the experiment.Results. We revealed the earlier changes in HCA animals (8th day of the experiment) induced by cerebral hypoperfusion accompanied by a more intense nNOS-positive neurons density reduction to 47 % of control values, the length of their processes, and an increase in pericarion area. In LCA the decrease of density was only 75 % of control values and pericarion area does not differ from control values. At later periods on the 60 and 90 days of the experiment LCA demonstrates the preservation of the neurons density and greater length of their processes (67 % of the control subgroup values).Conclusion. HCA is a risk factor for damage of nNOS-positive neurons in cerebral hypoperfusion. Physical exercise more effectively decreases nNOS expression in animals with HCA, which may be one of the sanogenetic mechanisms of this factor.