Resumo

Objectives: Inflammatory response in brain is primarily mediated by microglia, but growing evidence suggests a crucial importance of astrocytes. S100B, a calcium-binding protein secreted by astrocytes, has been assumed as a neurotrophic cytokine. The aim of this study was to investigate the S100B secretion and the immunocontent of S100B and glial fibrillary acidic protein (GFAP) in astrocyte cultures. Methods: Primary astrocyte cultures were prepared from cerebral cortex of newborn Wistar rats. Cultures were allowed to grow to confluence and the medium was replaced by DMEM without serum and lipopolysaccharide (LPS), concentrations range from 0.01 to 30 µg/mL for 1 and 24 h. S100B and GFAP measurements were carried out by ELISA. Cell viability was measured by neutral red uptake and MTT reduction assays. Results: LPS induced an increase in S100B secretion after 1 h at 10 µg/mL (0.039 ng/mL ± 0.005, n = 6) and 30 µg/mL (0.062 ng/mL ± 0.012, n = 6) compared to basal condition (0.021 ng/mL ± 0.007, n = 6). Conversely, after 24 h of exposure to LPS 0.01 µg/mL (0.56 ng/mL ± 0.06, n = 6), we observed a decrease in S100B secretion in comparison to basal condition (0.88 ng/mL ± 0.11, n = 6). However, all the concentrations of LPS were able to induce an increase in GFAP immunocontent 24 h afterwards. We did not observe significant changes in the intracellular content of S100B. No changes in MTT reduction and neutral red assay were observed. Conclusion: These data contribute to understanding the astroglial activity during neuroinflammation and the effect of LPS on primary astrocytes, particularly on S100B secretion and GFAP content.