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

Abstract

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 3 h. Blood and kidney samples were obtained before reperfusion and at 1, 2, 3, and 12 h after reperfusion. For the control group, mice were kept for 6 h under an anesthetized condition without rubber bands. Blood gases and biochemical parameters were analyzed by i-STAT®300F. 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.