Inhibition of KCa3.1 Channels Suppresses Atrial Fibrillation via the Attenuation of Macrophage Pro-inflammatory Polarization in a Canine Model With Prolonged Rapid Atrial Pacing

Figures

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  Figure 1. Mean AF inducibility, AF duration and AERP in all groups. (A,B) The mean AERP in both LA and RA was substantially greater in the pacing group than in the other two groups, and the pacing+TRAM-34 group was substantially greater than in the sham group. (C) The mean AF incidence rate was substantially greater in the pacing group than in the other two groups, and for the pacing+TRAM-34 group it was substantially greater than in the sham groups. (D) The mean AF duration was substantially greater in the pacing group than that in the other two groups, and in the pacing+TRAM-34 group it was substantially greater than in the sham group. P** < 0.01 vs. the sham group, P*** < 0.001 vs. the sham group. PΔΔ < 0.01 vs. the pacing group, PΔΔΔ < 0.001 vs. the pacing group. AF, atrial fibrillation; AERP, atrial effective refractory period; RA, right atrium; LA, left atrium.

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  Figure 2. (A) Representative atrial sections double labeled immunofluorescence for KCa3.1 and CD68-marked macrophage (while arrow). (B) Immunofluorescence analysis indicated that the expression of KCa3.1 in macrophage in the atrium was significantly higher in the pacing group than in the sham group and pacing+TRAM-34 group. (C) Immunofluorescence analysis indicated that the overall expression level of KCa3.1 (mainly in cardiomyocytes according to the immunofluorescence figure) in the atrium was significantly higher in the pacing group than in the sham group and pacing+TRAM-34 group. (D–G) Western blotting demonstrated that the expression of KCa3.1 in the LA and RA was higher in the pacing group compared with the control and pacing+TRAM34 groups. There was no significant difference in the expression of KCa3.1 between the LA and the RA in the three groups, respectively. (H) Quantitative analysis of M1 macrophages in sections of atrial samples (n = 4). The number of M1 macrophages was significantly higher in the pacing group than in the sham or pacing+TRAM-34 groups. The number of M1 macrophage in atrium was higher in the pacing+TRAM-34 group than that in the sham group. (I,J) The expression…

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  Figure 3. Expression of IL-1β, TNF-α, and MCP-1 in all groups. (A–F) Levels of IL-1β, TNF-α, and MCP-1 in both the LA and RA were markedly higher in the pacing group compared with the sham or pacing+TRAM-34 groups. The levels of IL-1β, TNF-α, and MCP-1 in both the LA and RA were higher in the pacing+TRAM-34 group than in the sham group. P** < 0.01 vs. the sham group, P*** < 0.001 vs. the sham group. PΔΔΔ < 0.001 vs. the pacing group. In our experiment, the same GAPDH was used for TNF-α, MCP-1, and the same GAPDH was used for IL-β, p38, c-Fos. IL-1β, interleukin-1 beta; TNF-α, tumor necrosis factor-alpha; MCP-1, monocyte chemotactic protein 1; LA, left atrium; RA, right atrium.

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  Figure 4. Expression of c-Fos, p38, and NF-κB p65 in all groups. (A–F) The levels of c-Fos, p38, and NF-κB p65 in both the LA and RA were markedly higher in the pacing group, compared with the sham or pacing+TRAM-34 groups. The levels of c-Fos, p38, and NF-κB p65 in both the LA and RA were higher in the pacing+TRAM-34 group than in the sham group. P* < 0.05 vs. the sham group, P** < 0.01 vs. the sham group, P*** < 0.001 vs. the sham group. PΔ < 0.05 vs. the pacing group, PΔΔ < 0.01 vs. the pacing group, PΔΔΔ < 0.001 vs. the pacing group. In our experiment, the same GAPDH was used for TNF-α, MCP-1, and the same GAPDH was used for IL-β, p38, c-Fos. NF-κB, nuclear factor kappa-B; LA, left atrium; RA, right atrium.