Figure 2.

Interleukin-6 overexpression in myeloid cells evokes significant vascular dysfunction, increased oxidative stress formation, and an increased reactivity of myeloid cells. (A) Aortic constriction studies. Left panel: aortic constriction in response to prostaglandin F2α and potassium chloride, analysed by unpaired Student’s t-test. Middle panel: isometric tension studies of LysM-IL-6^OE and control aortas in response to acetylcholine, analysed by two-way ANOVA with Bonferroni’s multiple comparisons. Right panel: statistical analysis of acetylcholine -induced maximal relaxation with unpaired Student’s t-test. n = 5–11 mice. P = 0.0499 (prostaglandin F2α), P = 0.0002 (maximal relaxation acetylcholine). (B) Mesenteric artery contraction and relaxation. Left panel: contraction of mesenteric arteries in response to potassium chloride in LysM-IL-6^OE and control mice, analysed by unpaired Student’s t-test. Right panel: relaxation to acetylcholine of mesenteric arteries that have been precontracted with phenylephrine, Mann–Whitney test, n = 8. P < 0.0001 (maximal relaxation acetylcholine). (C) Reactive oxygen species/reactive nitrogen species levels in whole blood after 20 min stimulation with phorbol 12,13-dibutyrate in LysM-IL-6^OE vs. controls, n = 6–8, unpaired Student’s t-test. P = 0.003. (D) Flow cytometric analysis of reactive oxygen species levels detected by CellRox Deep Red staining in CD11b⁺ myeloid cells in blood of LysM-IL-6^OE mice compared with controls with and without phorbol 12,13-dibutyrate stimulation. Pre-gating on living and CD45.2⁺ cells. Kruskal–Wallis test with Dunn’s multiple comparison test. Quantification left panel: representative flow cytometry histograms; right panel. n = 7–8 mice. P = 0.0045 (control vs. LysM-IL-6^OE + phorbol 12,13-dibutyrate), P = 0.0035 (LysM-IL-6^OE vs. LysM-IL-6^OE + phorbol 12,13-dibutyrate). Data are presented as mean ± SEM, and P values of <0.05 were considered significant and marked by asterisks (*P < 0.05; **P < 0.01; ***P < 0.001).