Resumo

We have been observed that rat cortical astrocytes responded to Neospora caninum infection in vitro, producing the proinflammatory cytokine TNF��. Flavonoids derived from plants are active compounds responsible for various biological effects including anti-inflammatory activity. In this study we investigated the effect of ten flavonoids, on astrocyte/microglia viability and reactivity, and its impacts on N. caninum infection. Astrocyte/microglia mixed primary cell cultures derived from newborn rat cortical brains were treated for 24h with flavonoids (50��M), after that infected with NC-1 tachyzoites (ratio of 1:1), and analyzed after 24 h infection. We observed, by the MTT test, that in both uninfected and N. caninum infected cultures flavonoids 3�f,4�f dihydroxyflavone, 7,8-dihydroxyflavone, luteoline (3',4',5,7-Tetrahydroxyflavone), kaempferol (3,4��,5,7-Tetrahydroxyflavone), fisetin (3,3��,4��,6-Tetrahydroxyflavone), quercetin (3,3��,4��,5,6-pentahydroxyflavone) and rutin (quercetin-3-rutinoside) stimulated significantly the mitocondrial activity of glial cells. Immunocytochemistry analyses revealed that stimulatory flavonoids also induced changes on astrocyte, microglia morphology and GFAP expression, OX-42 respectively. Moreover, we observed an increase on TNF�� secretion in cultures exposed to flavonoids presenting a catechol group. These data show that glial cells response to flavonoids differently, depending on its structure and hydroxylation degree, and interfere on N. caninum infection and proliferation. Supported by CNPq.