Endotoxin tolerance enhances interleukin-10 renal expression and decreases ischemia-reperfusion renal injury in rats

The potential implication of interleukin (IL) 6, tumor necrosis factor alpha (TNF-alpha), and IL-10 in the protective effect of low-dose lipopolysaccharide (LPS) administration against renal ischemia-reperfusion injury was evaluated in a rat model. Eighteen male Sprague-Dawley rats were injected intravenously with either 0.5 mg/kg of LPS (tolerant group) or saline (control group) 2 days before surgery. Ischemic renal injury was induced by clamping the left renal artery for 60 min on rats immediately after right-side nephrectomy. Reperfusion was obtained by clamp removal and was studied at RO (no reperfusion), 2H (R2), and 24H (R24) by renal tubular disorder characterization and by plasma creatinine as well as renal cytokine (IL-6, IL-10, and TNF-alpha) studies. No differences were observed between the two groups as concerns the period immediately after renal ischemia (RO). The endotoxin-tolerant group was associated with a significantly lower creatinine level at R24 (231 +/- 28 vs 315 +/- 36 mu mol/L; P = 0.007). Pretreatment with LPS significantly reduced the degree of proximal tubule necrosis and outer medulla congestion. In such tolerant animals, renal IL-6 production was decreased, whereas IL-10 production was significantly increased at R2 and R24. There were no differences in TNF-alpha renal production. In this study, we demonstrated that administration of low doses of LPS to rats had a protective effect from renal reperfusion injury, and our data suggest that IL-10 might play a role in this phenomenon.