Fig. 1
SNI-induced chronic neuropathic pain provides cardioprotection against IR injury. a Schematic of experimental design showing the timeline for SNI surgery (D0) and myocardial IR surgery (D5). b Left panel, representative images of TTC staining showing area of infarct region (pale color) and AAR in heart cross-sections from different treatments. Evans blue dye was injected retrogradely from aorta into coronary circulation to delineate the remote area. The infarcted size was determined by TTC (1%) staining. Right panel, quantification results of infarct size and AAR. *p < 0.05 SNI vs. sham and naïve groups. c Percentage of fractional shortening (% FS) and ejection fraction (% EF) from sham and SNI groups by echocardiography. *p < 0.05 SNI vs. sham. d Representative images of H&E staining (left panel) and picrosirius red staining (right panel) of cardiac sections 4 weeks after IR injury from sham and SNI groups. Areas marked by white rectangles were magnified and shown in the middle panel. Scale bar = 1 mm and 50 μm. Bar graph, quantification results of fibrosis in left ventricles. *p < 0.05 SNI vs. sham. e Upper panel, immunoblotting of cleaved caspase 3 from left ventricle lysate 24 h after IR in SNI or sham groups. Lower panel, quantification results of cleaved caspase 3 immunoblotting. *p < 0.05 SNI vs. sham. f Representative images of TUNEL stain in cardiac sections (red: α-actinin, green: TUNEL signal, blue: DAPI). Quantification was conducted by entire slices scanning and TUNEL-positive signals (green fluorescence) were normalized to total nuclei (DAPI, blue fluorescence). Apoptotic activity was assayed by TUNEL stain 24 h after IR injury in SNI or sham groups. *p < 0.05 SNI vs. sham group. Scale bar = 50 μm (left panel) and 10 μm (right panel). g Representative immunoblotting and quantification of cytosolic and membrane fraction of PKCε in left ventricular lysate. *p < 0.05 SNI vs. sham group. Error bars indicate SEM. Sample numbers are indicated within parentheses in all figures. Statistical significance was determined by one-way ANOVA (b) or Student’s t-test (c–g)
