Interleukin-9 Deletion Relieves Vascular Dysfunction and Decreases Blood Pressure via the STAT3 Pathway in Angiotensin II-Treated Mice

Figure 1. Effects of Ang II treatment on IL-9 expression. (a) Aortic IL-9 and IL-9R expressions were measured at different time points of Ang II infusion. (b) Aortic mRNA expression of IL-9 and IL-9R of each group was determined. (c) Serum IL-9 levels were detected at each time point. (d) Aortic IL-9 and IL-9R expressions were investigated at different doses of Ang II at the end of four weeks. (e) IL-9 mRNA and IL-9R mRNA in aortas of mice treated with different concentrations of Ang II were detected. (f) Serum IL-9 levels were determined when different Ang II doses were administered. N = 5‐6 for each group. ∗p < 0.05 vs. the control group; #p < 0.05 vs. the Ang II (1 W) group or the Ang II (250 ng/kg/mini) group; &p < 0.05 vs. the Ang II (500 ng/kg/min) group.

Figure 2. Effects of IL-9 KO on Ang II-induced hypertension. (a) Systolic blood pressure (SBP) of saline and angiotensin II-infused mice was measured using the tail-cuff method. (b–d) SBP, diastolic BP, mean arterial pressure, and heart rate were detected using the Millar Pressure Volume System. N = 10 for each group; ∗p < 0.05 vs. the WT Sham group; #p < 0.05 vs. the WT Ang II group.

Figure 3. The regulatory effect of IL-9 KO on vascular dysfunction. (a) The effect of IL-9 KO on ACh-induced relaxation was measured in endothelial-intact aortas isolated from the four groups. (b) The effect of IL-9 KO on PE-induced contraction was measured in endothelial-intact aortas isolated from each group. (c) The effect of IL-9 KO on SNP-induced relaxation was measured in endothelial-intact aortas isolated from each group. (d) Effect of indomethacin on ACh-induced relaxation. N = 5 in each group. ∗p < 0.05 vs. the WT Sham group; #p < 0.05 vs. the WT Ang II group; &p < 0.05 vs. the IL-9-/- Ang II group.

Figure 4. Effects of IL-9 KO on inflammatory response. (a) STAT3 phosphorylation for the four groups was measured. (b) The expression of aortic IL-1β, IL-6, IL-17, TNF-α, IFN-γ, MCP-1, IL-4, IL-10, and IL-13 mRNA in each group was analyzed. (c) Serum levels of these cytokines were detected using ELISA. N = 5 in each group. ∗p < 0.05 vs. the WT Sham group; #p < 0.05 vs. the WT Ang II group.

Figure 5. Effects of IL-9 KO on phenotypic transformation of smooth muscle. (a) Aortic OPN and SM22α expressions for the four groups were measured. N = 5 in each group. ∗p < 0.05 vs. the WT Sham group; #p < 0.05 vs. the WT Ang II group. (b) Effects of rIL-9 and S31-201 on the OPN and SM22α mRNA expressions of Ang II-treated SMCs. N = 5 in each group. ∗p < 0.05 vs. the control group; #p < 0.05 vs. the Ang II group; &p < 0.05 vs. the Ang II+rIL-9 group.

Figure 6. Effects of S31-201 on blood pressure, inflammation, and phenotypic transformation of smooth muscle. (a, b) Blood pressure was determined using the tail-cuff method and the Millar Pressure Volume System; N = 10 in each group. (c) The STAT3 phosphorylation in each group was measured. (d) The vascular function for the four groups was detected. (e) Serum cytokine levels were measured using ELISA kits. (f) Aortic mRNA expression of cytokines was analyzed by RT-PCR. N = 5 in each group; ∗p < 0.05 vs. the IL-9-/- Ang II+DMSO group.

Figure 7. Serum IL-9 levels in patients with hypertension. (a) Serum IL-9 levels were measured using ELISA in patients with hypertension and control subjects. (b) Correlation analysis of SBP and IL-9 levels in patients with hypertension. (c) Correlation analysis of DBP and IL-9 levels in patients with hypertension. ∗∗∗∗p < 0.0001 vs. the control group.