P2X7 receptor inhibition prevents atrial fibrillation in rodent models of depression

Figures

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  Figure 1. Depressive-like behaviours and AF inducibility in LPS-induced depression. (A) Schematic diagram of the experimental procedure. (B) Sucrose preference in the SPT. n = 10 per group. (C) Immobility in the FST. n = 10 per group. (D) Representative recordings of burst pacing protocol. (E and F) Inducibility and duration of AF, respectively. n = 8 per group. *P < 0.05, ***P < 0.001 vs. CTL; #P < 0.05, ###P < 0.001 vs. LPS. SPT, sucrose preference test; FST, forced swimming test; SR, sinus rhythm; R, R-wave; AFL, atrial flutter; AF, atrial fibrillation.

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  Figure 2. Expression of P2X7R and NLRP3 inflammasome-related indicators in LPS-induced depression. (A and B) Immunoblotting and expression ratio of P2X7R, respectively. n = 4 per group. (C–F) Immunoblotting and expression ratio of NLRP3, ASC, and Caspase-1, respectively. n = 4 per group. *P < 0.05, **P < 0.01, ***P < 0.001 vs. CTL; #P < 0.05, ##P < 0.01, ###P < 0.001 vs. LPS.

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  Figure 3. Depressive-like behaviours in CUS-induced rats. (A) Schematic diagram of the experimental procedure. (B) Body weight. n = 10 per group. (C) Sucrose preference in the SPT. n = 10 per group. (D) Immobility in the FST. n = 10 per group. ***P < 0.001 vs. CTL; ###P < 0.001 vs. CUS. SPT, sucrose preference test; FST, forced swimming test.

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  Figure 4. Expression of P2X7R in CUS-induced rats. (A and B) Immunoblotting and expression ratio of P2X7R, respectively. n = 6 per group. (C and D) Representative images of double-immunofluorescent labelling of P2X7R and Cardiac troponin T, and the mean fluorescence intensity of P2X7R, respectively. n = 4 per group. (E) Negative control was performed using specific IgG instead of the P2X7R antibody. Scale bar: 50 μm. **P < 0.01, ***P < 0.001 vs. CTL; #P < 0.05, ###P < 0.001 vs. CUS. AU, arbitrary units.

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  Figure 5. Electrophysiological phenotypes in CUS-induced rats. (A) Representative recordings of MPA in S1–S2 stimulation protocol. (B and C) ERP and AL, respectively. n = 10 per group. (D) Representative recording of MAP in S1–S1 stimumlation protocol. (E) APD90, n = 10 per group. (F) Representative recordings of burst pacing protocol. (G) Inducibility of AF. n = 10 per group. (H) Duration of AF. n = 9 in CUS and n = 3 in CUS + B. ***P < 0.001 vs. CTL; #P < 0.05, ##P < 0.01, ###P < 0.001 vs. CUS. ERP, effective refractory period; AL, atrial latency; MAP, monophasic action potential; APD90, action potential duration at 90% repolarization; SR, sinus rhythm; R, R-wave; AF, atrial fibrillation.

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  Figure 6. ECG and HRV parameters in CUS-induced rats. (A–E) Average P-average duration, Pmin, Pmax, P-wave dispersion, and P–R interval, respectively. n = 6 per group. (F–L) HR, R–R interval, SDNN, RMSSD, LF, HF, and LF/HF, respectively. n = 6 per group. *P < 0.05, **P < 0.01, ***P < 0.001 vs. CTL; #P < 0.05, ##P < 0.01, ###P < 0.001 vs. CUS. HRV, heart rate variability.

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  Figure 7. Expression of GAP43 and TH in CUS-induced rats. (A–C) Immunoblotting and expression ratio of GAP43 and TH, respectively. n = 5 per group. *P < 0.05, ***P < 0.001 vs. CTL; #P < 0.05, ###P < 0.001 vs. CUS.

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  Figure 8. Atrial fibrosis in CUS-induced rats. (A–B) Representative images of Masson staining in atria and quantification of the fibrotic area, respectively. n = 5 per group. Scale bar: 100 μm. (C–F) Immunoblotting and expression ratio of COL-I, COL-III, and TGF-β, respectively. n = 5 per group. ***P < 0.001 vs. CTL; #P < 0.05, ##P < 0.01, ###P < 0.001 vs. CUS.

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  Figure 9. Protein expression of ion channels and connexins in CUS-induced rats. (A–E) Immunoblotting and expression ratio of Nav1.5, Cav1.2, Kv1.5, and Kv4.3, respectively. n = 5 per group. (F–H) Immunoblotting and expression ratio of Cx40 and Cx43, respectively. n = 5 per group. *P < 0.05, **P < 0.01, ***P < 0.001 vs. CTL; #P < 0.05, ##P < 0.01, ###P < 0.001 vs. CUS.

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  Figure 10. Expression of TLR4/NF-κB/NLRP3 pathway-related indicators in CUS-induced rats. (A–E) Immunoblotting and expression ratio of TLR4, p65, p-p65, NLRP3, ASC, Caspase-1, and IL-1β, respectively. n = 5 per group. **P < 0.01, ***P < 0.001 vs. CTL; #P < 0.05, ##P < 0.01, ###P < 0.001 vs. CUS.

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  Figure 11. Depressive-like behaviours and electrophysiological phenotypes in CUS-induced mice. (A) Schematic diagram of the experimental procedure. (B) Sucrose preference in the SPT. n = 8 per group. (C) Immobility in the FST. n = 8 per group. (D–F) ERP, AL, and APD90, respectively. n = 8 per group. (F) Inducibility of AF. n = 8 per group. (G) Duration of AF. n = 7 in CUS-WT and n = 1 in CUS + KO. **P < 0.01, ***P < 0.001 vs. CTL-WT; #P < 0.05, ##P < 0.01, ###P < 0.001 vs. CUS-WT. SPT, sucrose preference test; FST, forced swimming test; ERP, effective refractory period; AL, atrial latency; APD90, action potential duration at 90% repolarization; AF, atrial fibrillation.

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  Figure 12. ECG and HRV parameters in CUS-induced mice. (A–E) Average P-average duration, Pmin, Pmax, P-wave dispersion, and P–R interval, respectively. n = 6 per group. (F–I) HR, R–R interval, SDNN, and RMSSD, respectively. n = 6 per group. **P < 0.01, ***P < 0.001 vs. CTL-WT; #P < 0.05, ##P < 0.01 vs. CUS-WT. HRV, heart rate variability.