THE NEURODEGENERATION PROCESS IN THE STRIATUM OF MICE EXPOSED TO OBESOGENIC DIETS

Abstract: Obesity and diabetes are known to impact brain function and alter metabolism. Studies in rodents show that consumption of high fat and high sugar diets lead to brain dysfunction affecting memory and cognition, and increases risk of cerebro-vascular and neurodegenerative disorders. Striatum, which is involved in reward-based behaviour and motor control, undergoes changes on exposure to such diets leading to movement defects, loss of impulse control, increased susceptibility to neurotoxins like MPTP and 6-OHDA. This effect is brought about by insulin resistance and loss of dopaminergic neurons thereby reducing dopamine signalling. In this study, striatal degeneration was investigated by measuring levels of synaptic proteins by immunoblotting and evaluating the phenotype of glial cells in mice exposed to fat-rich diets (10%, 45% and 60% of total energy intake) for 6 months. Relative to control fed the 10%-fat diet, mice fed 60% fat showed a decrease in levels of synaptic proteins Synaptosome-associated protein (SNAP25) and Syntaxin-1 whereas 45% fat diet reduced levels of Synaptophysin. The data from this study does not point to significant changes in dopamine signalling, astrogliosis or neuroinflammation. In sum, the trend observed in terms of reduction in levels of synaptic proteins that are crucial for maintaining efficient synaptic plasticity is likely to cause to neuronal networks involving the striatum, which controls, motor function and emotional behaviours.