Effect of Cardarine on Gene Expression of Proteins Involved in Epileptogenesis in Rat Hippocampus in the Lithium-Pilocarpine Model of Temporal Lobe Epilepsy

Abstract

During the last years, the role of astro- and microglial cells and associated neuroinflammation in the pathogenesis of epilepsy has been extensively discussed. These cells can be in different functional state. The extreme A1 and M1 phenotypes producing predominantly pro-inflammatory (promoting epileptogenesis) proteins and the A2 and M2 phenotypes producing anti-inflammatory (preventing epileptogenesis) proteins. It has been suggested that the use of drugs that can stimulate polarisation from M1 and A1 to M2 and A2 phenotypes may be a successful strategy for the treatment of epilepsy. Such drugs include agonists of peroxisome proliferator-activated receptor nuclear receptors (PPARs). The aim of this study was to investigate changes in the expression of micro- and astroglial proteins involved in the regulation of epileptogenesis in the dorsal hippocampus of rats in the lithium-pilocarpine model of temporal lobe epilepsy (TLE) and to investigate the effect of the PPAR agonist beta/delta cardarine on these processes. Cardarine was administered at the initial stages of epileptogenesis (within 7 days after induction of the TLE model), and two months later (chronic phase of the model) we analysed the expression of genes of interest in the dorsal hippocampus by real-time RT-PCR. The performed study revealed changes in gene expression of astro- and microglial proteins during epileptogenesis, mainly associated with the enhancement of neuroinflammatory processes and weakening of neuroprotective properties of these cells. In TLE rats the expression of genes of markers of astro- (Gfap) and microglia activation (Aif1), pro- (Il1b, Nlrp3) and anti-inflammatory (Il1rn) proteins, markers of the A1 phenotype of astrocytes (Lcn2, Gbp2) and growth factors (Bdnf, Fgf2) was increased. Gene expression of the protective M2 phenotype Arg1 gene was decreased in TLE rats. The most striking effect of cardarine administration was manifested in the enhanced expression of the marker A2 gene of the S100a10 astrocyte phenotype.