Aims of the study: To investigate the effect of water extract of Rhizoma coptidis (WEC) and berberine on the activation of murine microglia N9 cells and corresponding mechanism related to mitochondria.
Materials and methods: Phagocytic activity of murine microglia N9 cells was measured by neutral red staining method after the cells were treated with various concentrations of WEC and alkaloids for 24h. Flow cytometric analysis was performed to determine the level of intracellular ROS, Ca(2+), and mitochondrial transmembrane potential (Delta psi) after 87 microg/ml of WEC and 12.4 microg/ml of berberine treatment. Global changes of gene expression in WEC- and berberine-treated N9 cells were measured using cDNA microarray.
Results: WEC and berberine, but not palmatine and jatrorrhizine, enhanced phagocytic activity of murine N9 cells in a dose-dependent manner. Both of WEC and berberine stimulated free radical generation, enhanced mitochondrial Delta psi and induced gene expression of Ndufab1, Cox6a2 and Atp5a1. However, a more significant phagocytic effect was observed for WEC. WEC, but not berberine, increased intracellular Ca(2+) concentration. The gene expression of Atp5c1 was selectively up-regulated by WEC, while three genes of Uqcrq, Cox8b, and Atp5g2 were induced by berberine.
Conclusions: WEC and berberine activated murine microglia N9 cells by the regulation of mitochondrial function and mitochondria-related signal molecules. The action of WEC is stronger than that of berberine, indicating that the effect of WEC is ascribed partially, but not totally, to berberine.
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