High-fat diet (HFD) consumption is associated with cognitive deficit and neurodegenerative diseases. The HFD effects on the central nervous system could be related to neuroinflammation, and even consumption of HFD for a short time period has been shown to exacerbate the inflammatory response to a mild immune challenge. The hippocampus is one of the most vulnerable brain regions to HFD-induced alterations. α-MSH is a potent anti-inflammatory peptide and previous results of our group indicated that α-MSH could reverse the effect of acute neuroinflammation on memory consolidation and reconsolidation. Here we studied the effect of HFD (60% of calories from fat) consumption on cognitive deficits. HFD impaired contextual fear (hippocampal dependent) memory if it is consumed during a long-term, and also after short-term consumption in rats that received a mild immune challenge (LPS 10µg/Kg). The treatment with α-MSH (0.1ug/0.25ul) in dorsal hippocampus reversed the effect of short-term HFD in contextual fear memory. We also determined possible changes in hippocampal structural plasticity. Preliminary results showed no differences in total spine density in dorsal hippocampus. Besides, we determined that the expression of GFAP was decreased.
Our present results indicate that HFD consumption for a short period sensitizes SNC to mild immune challenge and produces impairment in the contextual fear memory that could be reversed by α-MSH and could be related to changes in glial cells.