Reduction of pulmonary inflammatory response by erythropoietin in a rat model of endotoxaemia / 中华医学杂志(英文版)

ABSTRACT

<p><b>BACKGROUND</b>Erythropoietin elicits protective effects in lung tissue injury induced by ischaemic reperfusion and hyperoxia. We investigated the protective roles of erythropoietin in pulmonary inflammation and lung injury during acute endotoxaemia.</p><p><b>METHODS</b>A total of 32 male Sprague-Dawley rats were randomly assigned to four groups saline group, erythropoietin + saline group, saline + lipopolysaccharide group and erythropoietin + lipopolysaccharide group. Rats were treated with erythropoietin (3000 U/kg, i.p.) or saline, 30 minutes prior to lipopolysaccharide administration (6 mg/kg, i.v.). Four hours after lipopolysaccharide injection, samples of pulmonary tissue were collected. Optical microscopy was performed to examine pathological changes in lungs. Wet/dry (W/D) ratios, myeloperoxidase activity, malondialdehyde concentrations and tumour necrosis factor-alpha (TNF-alpha) as well as interleukin 1 beta (IL-1beta) levels in lungs were measured. The pulmonary expression of nuclear factor kappaB (NF-kappaB) p65 was evaluated by Western blotting. Differences between the different groups were analysed by one-way analysis of variance (ANOVA).</p><p><b>RESULTS</b>The lung tissues from the saline + lipopolysaccharide group were significantly damaged, which were less pronounced in the erythropoietin + lipopolysaccharide group. The W/D ratio increased significantly in the saline + lipopolysaccharide group (5.75 +/- 0.22) as compared with the saline group (3.85 +/- 0.20) (P < 0.01), which was significantly reduced in the erythropoietin + lipopolysaccharide group (4.50 +/- 0.35) (P < 0.01). Myeloperoxidase activity and malondialdehyde levels increased significantly in the saline + lipopolysaccharide group compared with the saline group, which was reduced in the erythropoietin + lipopolysaccharide group. The TNF-alpha level of pulmonary tissue increased significantly in the saline + lipopolysaccharide group ((9.80 +/- 0.82) pg/mg protein) compared with the saline group ((4.20 +/- 0.42) pg/mg protein, P < 0.01). However, the increase of TNF-alpha level of pulmonary tissue was significantly reduced in the erythropoietin + lipopolysaccharide group ((6.50 +/- 0.66) pg/mg protein, P < 0.01). Similarly, pulmonary IL-1beta levels were elevated markedly in the saline + lipopolysaccharide group in contrast to the saline group, whereas the elevation was much less in the erythropoietin + lipopolysaccharide group. The nuclear localization of p65 increased markedly in the saline + lipopolysaccharide group and this enhancement of nuclear p65 expression was much less in the erythropoietin + lipopolysaccharide group.</p><p><b>CONCLUSION</b>Erythropoietin attenuates pulmonary inflammation and suppresses TNF-alpha and IL-1beta overproduction during acute endotoxaemia, which is partially mediated by inhibition of NF-kappaB.</p>