Endoplasmic reticulum stress of astrocytes in paraventricular nucleus of hypothalamus promotes ventricular electrical instability after acute myocardial infarction in rats

Figures

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  Figure 1. General results and transcriptomic analysis results. (A) Changes of body surface ECG prior to, during, and 24 h following LADO; (B) Heart tissue of rats in SH group and AMI group; (C,D) Cardiac pathology of rats with AMI (scale = 500 μm, 50 μm); (E) Gene volcano map of differential expression of PVN tissue; (F) GO functional enrichment analysis of differentially expressed genes; (G) KEGG functional analysis showed 16 pathways with significant differential expression; (H) GSEA enrichment analysis showed that the difference of ER stress genes was most significantly increased. LADO, occlusion of left anterior descending coronary artery; SH, sham operation; AMI, acute myocardial infarction.

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  Figure 2. Immunohistochemical results and western blot analysis of the PVN. (A) Under a high magnification microscope (scale = 500 μm, 100 μm, 50 μm), the immunohistochemical results of the PVN in the four groups of rats showed that the GFAP immunopositive reaction. (B) The expression of GFAP protein in bilateral PVN was determined by western blot. (C) Immunohistochemical results of the PVN in the four groups showed that the number of c-Fos positive cells in AMI and AMI + Vehicle rats was higher than that in SH rats, as shown in the representative images of c-Fos immunopositive reaction under high magnification microscope (scale = 500 μm, 50 μm); (D) The expression of c-Fos protein in bilateral PVN was determined by western blot. SH, sham operation; AMI, acute myocardial infarction; GSK2606414: p-PERK inhibitor; GFAP, glial fibrillary acidic protein; Compared with SH group, *P < 0.05, **P < 0.01, n = 3.

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  Figure 3. Western blot analysis of ER stress-related proteins and inflammatory cytokines expression in the PVN. (A) Western blot results; (B) The expression of C3 protein in bilateral PVN was measured by western blot. SH: sham operation; (C) The expressions of GRP78, CHOP, PERK and p-PERK in the PVN were measured by western blot; (D,E) Expression of TNF-α and IL-6 protein. SH, sham operation; AMI, acute myocardial infarction; GSK2606414: p-PERK inhibitor; Compared with SH group, *P < 0.05, **P < 0.01, n = 3.

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  Figure 4. Results of intracardiac electrophysiological testing in four groups of rats. (A) ECG findings of VAs; (B) Comparison of the programmed stimulation maps of VERP and ERP of left ventricular IBA and IRA in each group of rats; (C) The programmed stimulus map of VFT and the comparison of VFT results; (D) VFI in each group of rats; (E) QT interval, Tp-e interval and QTc of rats in four groups; Influence of Tp-e/QT and Tp-e/QTc ratio; (F) The changes of plasma NA in four groups of rats; (G) There was no significant difference in mean arterial pressure changes in the four groups of rats. Compared with SH group, *P < 0.05; Compared with AMI + Vehicle group, #P < 0.05. SH, sham operation; AMI, acute myocardial infarction; GSK2606414: p-PERK inhibitor; NA, norepinephrine; MAP, marterial pressure; IBA, periinfarction area; IRA, infarct distal region; VERP ventricle, effective refractory period; VFT, ventricular fibrillation threshold; VF, ventricular fibrillation; VFI, ventricular fibrillation induction rate.

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  Figure 5. Western blot analysis of thaps on astrocytes. (A) Western blot results; (B) The expression of C3 protein in astrocytes was observed with an increased concentration of Thaps; (C) Expression of proteins associated with UPR initiated by ER stress in astrocytes under conditions of increased Thaps concentration; (D,E) Regulation of the expression of inflammatory factor protein in astrocytes by different Thaps concentrations. Compared with Thaps = 0 μM, *P < 0.05, n = 3.

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  Figure 6. Western blot analysis of the effect of GSK2606414 on thaps-induced astrocytes. (A) Western blot results; (B) Expression of C3 protein in astrocytes at increased concentration of PERK inhibitor GSK2606414; (C) Under conditions of increased concentration of PERK inhibitor GSK2606414, astrocytes were treated with Thaps (1 μM) for 24 h and then western blot was performed; results of TNF-α and IL-6 protein western blot analysis. Compared with Thaps = 0 μM/GSK2606414 = 0 μM, *P < 0.05, compared with Thaps = 1.0 μM/GSK2606414 = 0 μM, #P < 0.05, n = 6.