Interleukin-10 inhibits the in vivo and in vitro adverse effects of TNF-[alpha] on the endothelium of murine aorta

TNF-[alpha] is a proinflammatory cytokine and is an important mediator of maternal endothelial dysfunction leading to preeclampsia. In this study, we tested whether IL-10 protects against TNF-[alpha]-induced endothelial dysfunction in murine aorta. In in vitro experiments, aortic rings of C57BL/6 female mice were incubated in Dulbecco's modified Eagle's medium in the presence of either vehicle (distilled [H.sub.2]O), TNF-[alpha] (4 nmol/1), or recombinant mouse IL-10 (300 ng/ml) or in the presence of both TNF-[alpha] and IL-10 for 22 h at 37[degrees]C. In in vivo experiments C57BL6/IL-10 knockout female mice were treated with saline or TNF-[alpha] (220 ng x [kg.sup.-1] x [day.sup.-1]) for 14 days. Aortic rings were isolated from in vitro and in vivo experiments and mounted in a wire myograph (Danish Myotech) and stretched to a tension of 5 mN. Endothelium-dependent relaxation was assessed by constructing cumulative concentration-response curves to acetylcholine (ACh, 0.001-10 [micro]mol/l) during phenylephrine (10 [micro]mol/l)-induced contraction. As a result, overnight exposure of aortic rings to TNF-[alpha] resulted in significant blunted maximal relaxing responses ([E.sub.max]) to ACh compared with untreated rings (22 [+ or -] 4 vs. 82 [+ or -] 3%, respectively). IL-10 knockout mice treated with TNF-[alpha] showed significant impairment in ACh responses ([E.sub.max]) compared with C57BL/6 mice treated with TNF-[alpha] (51 [+ or -] 3 vs. 72 [+ or -] 3%, respectively). Western blot analysis showed that endothelial nitric oxide synthase (eNOS) expression was reduced by TNF-[alpha] in in vitro and in vivo experiments, whereas IL-10 restored the eNOS expression. In conclusion, the anti-inflammatory cytokine IL-10 prevents impairment in endothelium-dependent vasorelaxation caused by TNF-[alpha] by protecting eNOS expression. tumor necrosis factor-[alpha]; nuclear factor-[kappa]B doi: 10.1152/ajpheart.00763.2009.