Comparison of renal dysfunction in wild-type, IL-6 KO and iNOS KO mice hind limb tourniquet-reperfusion model

The release of a tourniquet after hind limb ischemia results in vital organ injury, which progresses to multiple organ failure with a high mortality rate. Many events are involved in ischemia-reperfusion (I/R) injury. The purpose of this study was to determine how IL-6 or iNOS is involved in I/R injury using IL-6 knockout (KO) and iNOS KO mice. Male C57BL/6J wild-type (WT), IL-6 knockout (KO) and iNOS KO mice were anesthetized with pentobarbital, and rubber bands were fastened to the inguinal region of both hind limbs for 3h. Blood and kidney samples were obtained before reperfusion and at 1, 2, 3, and 12h after reperfusion. For the control group, mice were kept for 6h under an anesthetized condition without rubber bands. Blood gases and biochemical parameters were analyzed by i-STAT300F. Real-time PCR analyses were performed to examine the expression levels of IL-6 and iNOS mRNA in kidneys. Metabolic acidosis, hemoconcentration and renal dysfunction were significantly developed after reperfusion regardless of mouse genotype, and progression of this condition was earlier in IL-6 KO and iNOS KO mice than in WT mice. The expression level of kidney IL-6 mRNA increased and that of iNOS mRNA decreased after reperfusion. It is possible that late decrease recovery of iNOS mRNA expression in IL-6 KO mice and early progress of IL-6 mRNA expression in iNOS KO mice after reperfusion induce renal dysfunction.