Activation of cultured mouse astrocytes by LPS and IFN-γ

Objective To investigate the effects of inflammatory chemokine LPS and/or IFN-γ on astrocytes. Methods After LPS and IFN-γ applied to the purified cultured mouse astrocytes, TNF-α and nitric oxide (NO) secreted from astrocytes and intracellular calcium concentration ([Ca2+]i) were detected by ELISA, Griess and confocal laser scanning microscopy, respectively. Results Treatment with LPS (500 ng/ml) or IFN-γ (100 U/ml) for 24 h significantly increased the concentration of TNF-α and NO. Coadministration of LPS and IFN-γ showed a synergistic effect on the astrocytes. By using Ca2+ imaging, we found that [Ca2+]i signal was significantly increased after LPS and/or IFN-γ treatment for 24 h. Also, acute treatment with LPS or IFN-γ could evoke Ca2+ oscillations. In contrast, after application of these stimuli over 24 h, the Ca2+ signal was increased more slowly. Conclusion Application of LPS and/or IFN-γ evoked TNF-α and NO secretion and [Ca2+]i elevation in cultured astrocytes, suggesting that astrocytes could be activated by LPS and IFN-γ.