Running Throughout Middle-Age Improves Memory Function, Hippocampal Neurogenesis, and BDNF Levels in Female C57BI/6J Mice

Marlatt, Michael W., et al. "Running throughout middle‐age improves memory function, hippocampal neurogenesis, and BDNF levels in female C57BL/6J mice." Developmental neurobiology 72.6 (2012): 943-952. I found this article to be relevant because I am interested in comparing BDNF levels within the RVLM of sedentary vs physically active animals. I am also interested in reading more about effects of exercise later in life than the "adolescent phase" due to the great technical difficulties we are facing imaging younger rats for MeMRI. Specifically, this article discusses the beneficial effects seen from chronic running during later stages in life. The model they used was a nine month old mouse model that exercised freely for 1 month prior to the first set of experiments and then another 5 months prior to the second set of experiments. As stated, at both 1 month and 6 months of exercising anxiety, memory, and motor tests were performed. Then at 8 months post exercise each of the animals were sacrificed and BDNF levels and BrDu positive neurons were examined. They found that after one month of exercising, mice exhibited less anxiety with increased central area during an arena test, as well as increased distance traveled. They also exhibited a tend toward increased latency between falls in a rotarod performance test measuring motor abilities. It was then seen that after 6 months of exercise animals showed increased social memory by increasing the amount of time within the target quadrant in a Morris water maze. These animals also trended towards a decreased number of falls during the rotarod test. To support these findings animals that had chronically run had increased levels of mature BDNF peptide within the hippocampus after 8 months. Exercising animals also had a greater number of BrDu labeled cells in the dentate gyrus, along with an increase in the total number of new neurons. Concluding, this study was able to show that chronic running later in life (9 months) improved spacial memory, motor skills, as well as decreased anxiety. This may be due to increased neurogenesis and neurotrophins in the hippocampus after 8 months of free exercise. I think it would be informative to compare BDNF levels, as well as neurogenesis within the RVLM between sedentary and physically active population. ~JI