Hippocampal electrophysiological responses and changes in oxidative stress marker and serum lipid profile to pharmacological and non-pharmacological treatments of high-fat-fructose diet induced metabolic syndrome

The aim of our study was to evaluate the possibility of influencing the risk factors of metabolic syndrome (MetS) and metabolic cognitive syndrome. As a model of MetS, we used high-fat-fructose diet (HFFD) fed hypertriacylglycerolemic (HTG) rats. Control group included HTG rats fed with HFFD during 8 weeks (HFFD8). Furthermore, we tested the effect of pharmacological and non-pharmacological therapies. Non-pharmacological therapy, which we chose, was a change in diet from HFFD (5 weeks) to standard one (3 weeks) and thus caloric restriction (HFFD5+3). The drug we used was rosmarinic acid (RA; 100mg/kg), which we administered to rats after 5 weeks of HFFD once a day for consecutive 3 weeks with current change in diet to standard one (HFFD5+3+RA) or during lasting last 3 weeks of HFFD (HFFD8+RA). After 8 weeks of experiment, lipid peroxidation markers, lipid profile of blood serum, and neuronal transmission and synaptic plasticity (long-term potentiation [LTP]) in hippocampal sections were evaluated in vitro. We observed a significant effect of dietary change in lipid profile (decreased total cholesterol and low-density lipoprotein cholesterol [LDL-cholesterol] and increased high-density lipoprotein cholesterol [HDL-cholesterol]). The combination of pharmacological and non-pharmacological treatments caused a decrease in total cholesterol, LDL-cholesterol, and lipid peroxidation in blood serum. Change in HFFD to standard diet without treatment resulted in slight improvement in neuronal transmission in the hippocampus and caloric restriction alone also had positive effect on LTP maintenance. Our results suggest that combination of pharmacological and non-pharmacological approaches had better impact on the biochemical parameters of MetS in blood serum, but weak impact on neuronal functions in the hippocampus, where the expected positive effect was achieved only by caloric restriction.