Figure 4

Serum from resistance-trained mice protects INS-1E cells from ER stress injury and apoptosis. INS-1E cells were incubated with conditioned medium with 10% of serum from control (striped black bar) or trained mice (striped red bar) for 24 h, followed by 16 h exposure to 25 µM CPA. Insulin secretion from INS1-E cells exposed to 2.8 or 22.2 mM glucose (n = 4) (a), Real-time PCR assay of PDX1 (b), Ins2 (c), BiP (d), XBP1 (e), ATF4 (f) and CHOP (g) mRNA levels (n = 6) in INS-1E cells from different treatments as indicated in the graph. The relative expression of mRNAs was determined after normalization with HPRT. Cell apoptosis was measured by HO and PI staining (n = 3–4). The % of dead cells (HO/PI stained cells ratio) is represented as % of control (Serum CON cells without CPA) (h). Data are the mean ± SEM. Different letters indicate statistic differences between groups, P ≤ 0.05 (One-Way ANOVA).