FIGURE 1.

Low doses of TM activated a non-toxic, mild ER stress in primary cultured astrocytes. (A) Primary astrocytes were treated with TM (0.01 to 10000 ng/ml) for 24 h followed by assessment of cell viability using the CCK-8 assay. (B) The expression levels of p-PERK, p-EIF2α, p-IRE1α, XBP1s, XBP1u, ATF4, and CHOP in primary cultured astrocytes were detected by Western blotting using specific antibodies. (C) Phosphorylated levels of PERK, EIF2α, and IRE1α were quantified and normalized to corresponding total levels. (D) Expression of XBP1s and XBP1u was quantified and normalized to Tubulin expression. (E) Expression of ATF4 and CHOP was quantified and normalized to Tubulin expression. Each value was then expressed relative to that of the control group, which was set to 100. All experiments were repeated three times. ^∗P < 0.05, ^∗∗P < 0.01 vs. control group. The data are presented as the mean ± SEM.