PPAR-γ agonist pioglitazone improved synaptic plasticity, anxiety and depression-like behaviors in lipopolysaccharide injected rats

Background and Aim : In present study the effects of PPAR-γ agonist pioglitazone on long term potentiation (LTP) and anxiety and depression-like behaviors in lipopolysaccharide (LPS) treated rats was investigated.Methods : The rats were divided into five groups: (1) control, (2) LPS (1 mg/kg), (3-5) three doses including 10, 20 and 30 mg/kg pioglitazone before LPS. The rats were used in two sets of the experiments. For assessment of depression and anxiety like behaviors LPS was injected 120 min before elevated plus maze, open field, or forced swimming test. For LTP experiment, LPS was injected during 6 days and also 120 min before the experiment. In both experiments, pioglitazone or vehicle was injected 30 min before LPS.Results : In open field, LPS increased the time and distance in the peripheral zone while, decreased these parameters in the central area. In elevated plus maze, LPS decreased the open arm time while increased the closed time. In forced swimming, LPS increased the immobility while, decreased the climbing time. Pretreatment by pioglitazone reversed the effects of LPS. The results of LTP experiment showed that the amplitude and 10-90% slope of field stimulation after synaptic potential (fEPSP) significantly decreased by LPS. Compared to the LPS, injection of 30 mg/ kg pioglitazone was followed by an increased level in fEPSP amplitude.Conclusion : In conclusion, the results of current study indicated that pioglitazone had anti- anxiety and anti- depressant effect and improved LTP impairments induced by LPS in rats.

Keywords:

Lipopolysaccharide , PPAR-γ agonist , Pioglitazone , Anxiety , Depression , Long term potentiation