The Effect of Combined Aerobic and Resistance Exercise Training on Passive Avoidance Learning, BDNF and Ki67 Levels of Hippocampus in Wistar Rats with Different Age Groups

The aim of the present study was to investigate the effect of 6 weeks of combined aerobic and resistance training on passive avoidance learning, BDNF and Ki67 levels in the hippocampus of Wistar rats at different age groups.

Thirty male wistar rats were prepared in three age groups of 2 weeks and 8 weeks and 24 months (n=10 in each), and each age group was divided into two groups of control and training (n=5 in each). In the training group, the animals performed resistance and aerobic training once a day. The amount of overload for the resistance training program was determined based on the body weight of the animals. For the aerobic training group, the intensity of training increased from 50% of the maximum speed in the first week to 80% in the last week. At the end of the study, passive avoidance learning was assessed by the shuttle box test.

The 24-month-old training group had a significant decrease in the number of round trips to darkness and light (frequency) compared to the 24-month-old control group (P<0.05). Although BDNF mRNA level was highest in the 2-week exercise group but was not significant compared to other exercise groups at different ages (P>0.05). Ki67 protein changes with Western blotting also showed that the 2-week age training groups and the 8-week age training group showed a significant increase compared to their control group (for both P=0.0001).

It seems that the older rats are less successful in behavioral tests than other ages due to more severe molecular damage in central nerve system (reduction of BDNF, Ki67), that performing combined exercise can effective in small amount.