Research Updates | Other
A new research study set out to examine the combined impact of early life stress and chronic sucrose availability on brain structure, function and gene expression.
The hippocampus is crucial for stress regulation and behavioural outcomes. Following an early life stress, it is not known if choice of diet can impact long-lasting molecular changes in this area of brain.
Female rats were exposed to early life stress, by limiting their nesting material (LN). Post-weaning, they were provided with a 25% sucrose solution. Rats were divided between a test (LN) and a control group, and had ad libitum access to either chow and water, or chow and sucrose solution. Biomarkers measured after 15 weeks of age were a selection of 16 genes related to stress regulation and nerve growth and development in the brain. Specifically, these were genes for plasticity, neurogenesis, stress and inflammatory response in the hippocampus, as well as 2 markers of DNA methylation.
The results showed that the majority of the selected genes were altered due to sucrose diet. Only one gene for inflammation (TLR4) was altered due to LN condition. There was no significant effect between diet and LN on selected genes. Neurod1 (plasticity and neurogenesis), GR (DNA methylation) and Akt3 (mitochondrial biogenesis) were significantly altered by both the LN and sucrose conditions independently. There was no significant effect on DNA methylation markers.
The authors conclude that early life stress and post weaning sucrose consumption in female rats had a long term effects on the expression of selected genes in the hippocampus. This may impact stress regulation and nerve growth and development in the future. They note that this is the first study to find chronic sucrose consumption alone produced similar outcome to early life stress. Whether similar effects are seen in male rats is unknown.
Maniam et al (2016) Sugar Consumption Produces Effects Similar to Early Life Stress Exposure on Hippocampal Markers of Neurogenesis and Stress Response. Frontiers in Molecular Neuroscience. 19 January 2016 doi: 10.3389/fnmol.2015.00086 http://journal.frontiersin.org/article/10.3389/fnmol.2015.00086/full