Effect of Aging and Regular Exercise on Prefrontal Cortex Histopathology, Myelin Density, and Antioxidant Activity of the Rats

Aging related to decline in physiological structure and functional capacity in brain. The aim of this research was to examine the differences in the pathophysiology of the prefrontal cortex (PFC) region between young and old rats.

 The young and old male Wistar rats (n= 40) were subgroups to normal young (NY), exercise young (EY), normal old (NO) and exercise old (EO). A forced aerobic exercise (FAE) program was established using a treadmill for 12 weeks. The exercise program including a turn off treadmill for normal groups while a turn on treadmill at a speed of 10-12 m/min for exercise groups. Toluidine blue and Cresyl-violet staining were used to evaluation of volume white matter (WM) and dark cell numbers in the prefrontal cortex (PFC). Levels of glutathione peroxidase (GPx) and malondialdehyde (MDA) were measured by spectrophotometric and Satoh methods, respectively. Afterward, the percentage of myelin basic protein (MBP) was assessed using immunohistochemical staining.

Our findings revealed a significant enhancement in the mean percentage of WM area, percentage of MBP and level of GPx in EO group compared to NO group (P ≤ 0.05). Also, the dark cell number and MDA level decreased in the old rats with exercise compared to NO group (P ≤ 0.05). However, there was no significant difference between other groups (P ≥ 0.05).  

The results indicated that normal aging has destructive effects on the PFC and antioxidants rate. However, the regular exercise with specialized program could improve deteriorate changes of aging on brain.