Exercise promotes cognition and hippocampal mitochondrial complex II expression in female rats

Evidence supports that exercise defends against age-associated declines in brain health and protects against neurodegenerative disease. To help understand the molecular basis for the neuroprotection, we examined the impact of training on mitochondrial protein expression within the exercise-brain axis. Thirty-two F344 rats (50% male/female) were assigned randomly to 10-week treadmill training or sedentary groups. Grip strength, Morris water maze and rotarod were used to assess muscular strength, spatial learning and motor coordination, respectively. Jess automated western blotting was used to quantify mitochondrial complex expression in hippocampus and soleus skeletal muscle samples. Values are means and standard deviation. Exercised females had better spatial memory (9.16 ± 8.70 vs. 32.7 ± 22.7 s, P = 0.043) and motor coordination (69.0 ± 16.1 vs. 47.5 ± 15.6 s, P = 0.042) as well as increased soleus mass (0.043 ± 0.003 vs. 0.039 ± 0.002% body mass, P = 0.039), hippocampal mitochondrial complex II expression (1.96 ± 0.38 vs. 1.11 ± 0.33 a.u., P = 0.007), and soleus mitochondrial complex III expression (6.68 ± 1.40 vs. 4.65 ± 1.26 a.u., P = 0.025) in comparison to sedentary females. Cognitive performance and hippocampal metabolic enzyme expression were concordantly increased following the 10-week exercise intervention in females but not males. These results provide novel support for the putative involvement of cerebral mitochondrial function in the beneficial relationship between exercise and brain health.