Kidney injury was determined in normal (unmanipulated) mice, and after sham, AKI or BNx at 4 and 24 hours in wild type (WT) and IL-6−/− mice. No kidney injury occurred after sham (surgery alone) in either WT or IL-6−/− as judged by (A) BUN, (B) plasma creatinine, (C) kidney KIM-1 mRNA, and (D) ATN score with (E) representative PAS images. Kidney injury was similar at 4 and 24 hours after AKI between WT and IL-6−/− mice as judged by (F) BUN, (G) plasma creatinine, (H) kidney mRNA KIM-1, and (I) ATN scores with (J) representative PAS images. Wild type and IL-6−/− mice with bilateral nephrectomy had similar levels of (K) BUN and (L) plasma creatinine. N=3 to 12 mice per group from 3 experiments. Results are expressed as mean ±SEM and analyzed by t test: WT versus IL-6−/− at the same time point (indicated above the bar) and versus normal WT (indicated below the bar: *P<0.05; **P<0.01, ***P < 0.0001). Scale bar: 100 μm.