Quercetin inhibits c-fos, heat shock protein, and glial fibrillary acidic protein expression in injured astrocytes

Quercetin, a bioflavonoid, is found widely in many kinds of fruits and vege tables. It is known to engage in many bioactivities, such as interfering wi th of the progress of stress responses to injury. In the present study, we investigated the effects of quercetin on some injury responses in primary c ultures of astrocytes. These injury responses included the elevation of c-f os protein, heat shock protein (HSP70), and glial fibrillary acidic protein (GFAP). After heat shock insult, the levels of c-fos protein and HSP70 in astrocytes increased. With quercetin treatment, these proteins were signifi cantly reduced. The inhibition of these injury responses by quercetin in as trocytes indicated a dose dependency, with the highest effect at 100 muM. W e have previously established a scratch injury model in a primary culture o f astrocytes. In that model, astrocytes responded to the scratch injury by an elevation in their GFAP level and formation of hypertrophic cell process es, which extend into the scratch areas. Quercetin treatment reduced the nu mber of hypertrophic cell processes being extended into the scratch areas. With 100 muM of quercetin, there was a complete inhibition of the formation of the hypertrophic cell process. Western blot analysis for GFAP indicated that quercetin significantly reduced the induction of GFAP in the scratch model. At 100 muM, the total GFAP content in the injured cultures was reduc ed to a level lower than that of the control. This implied that quercetin m ight possess an antigliotic property. J. Neurosci. Res. 62:730-736, 2000. ( C) 2000 Wiley-Liss, Inc.