Oral communications Imipramine, moclobemide and fluoxetine inhibit tumor necrosis factor- release by lipopolysaccharide-activated rat primary mixed glial cells

Numerous studies suggest that proinflammatory cytokines are involved in pathophysiology of depression and in the mechanism of action of antidepressant drugs. There are some clinical and experimental data indicating that antidepressants are able to reduce the levels of proinflammatory cytokines. Because the main source of cytokines in the brain are glial cells, the aim of our study was to investigate the influence of some antidepressants on tumor necrosis factor(TNF) release by lipopolysaccharide (LPS)-activated primary mixed rat glial cultures. Three antidepressants with different mechanism of action on monoaminergic systems: imipramine, moclobemide and fluoxetine were used. Mixed glial cultures were prepared from cerebral hemispheres of one day old newborn Wistar rats in Dulbecco’s Modified Eagle’s Medium supplemented with 10% heat-inactivated fetal bovine serum and 1% antibiotic solution. The cells were cultured for 12–14 days (37°C; 5% CO , 95% air, 80% humidity). Because the strongest stimulation of TNFrelease was observed when LPS was administrated at a concentration of 1 g/ml for 6 h, these parameters were applied in the experiments. Antidepressants were used at concentrations from 10 to 10 M/ml. Only fluoxetine was applied at concentrations up to 10 M because the higher concentration was cytotoxic as determined with the Trypan Blue exclusion method. Levels of TNFrelease were evaluated in culture medium with rat TNFELISA kits (R&D, USA). The intra-assay precision CV for TNFwas 7.4%. The cultures were stained with Ricinus communis agglutynin-1, lectin that binds to the surface glycoproteins on microglia (Vector, USA). The cells were examined using fluorescence microscope (TS-100/F, Nikon). The results of our study have shown that the studied antidepressants inhibit TNFsecretion by mixed glial cell cultures. Imipramine produced this effect at concentrations from 10 to 100 M, moclobemide from 10 to 10 M and fluoxetine – from 10 to 10 M. The obtained results support the previous observations that antidepressants are able to reduce the levels of proinflammatory cytokines and that TNFmay be involved in the central mechanism of action of imipramine, moclobemide and fluoxetine.