Protection effects of ulinastatin against lung warm ischemia-reperfusion injury in rats

Objective To investigate the protective effect of ulinastatin against lung ischemia-reperfusion injury in rats and to compare the contribution of two different doses. Methods Thirty Sprague Dawley rats were randomly divided into three groups,with 10 rats in each.In ischemia-reperfusion group(IR group),the hilum of left lung was blocked for 1 hour and was then reopened.After 2 hours of reperfusion,blood sample from the left pulmonary vein was taken and the oxygen partial pressure was measured before the rats were sacrificed.The upper part of left lungs was assayed for wet/dry weight ratio(W/D),the middle part was taken for microscopic study,the other parts were frozen in liquid nitrogen for detection of myeloperoxidase concentration(MPO);In ulinastatin conventional dose group(UC group) and ulinastatin high-dose group(UH group),the rats were intravenously administered 10 000 IU/kg and 20 000 IU/kg ulinastatin,respectively,before blocking the hilum of the left lungs.The other procedures were the same as in the IR group. Results Compared IR group with the UH group,there was statistically significant difference in PO2 and W/D [(109.5±18.3)mmHg vs.(128.5±17.7)mmHg,5.30±0.13 vs.5.08±0.25,P0.05].For the results of MPO concentration,among IR group,UC group and UH group,there was statistically significant difference between each two groups [(57.36±10.51)ng/mL,(45.74±8.13)ng/mL and(28.30±6.28)ng/mL,P0.05].Tissue slice(HE stain) showed inflammatory cells infiltration in IR group. Conclusions The present study demonstrates that ulinastatin has a protective effect on rat lung warm ischemia-reperfusion injury,which was dose-dependent.