Effects of siRNA of AMPK on APN-reduced expression of iNOS and nitrotyrosine and production of NO and ONOO−. A, Expression of iNOS. B, Expression of nitrotyrosine. C, Expression of AMPK on treatment with siAMPK (10 μm). D, Production of NO. E, Production of ONOO−. **, P < 0.01 vs. control group (con); ##, P < 0.01 vs. LPS; $$, P < 0.01 vs. APN + LPS. Values are means ± sem.