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Objective To observe the expression changes of FKN、MCP-1 in the lung and plasma respectively on ischemia-reperfusion rat model when protreated with EPO,and explore the possible mechanisms of EPO on lung ischemia-reperfusion injury of the rats.Methods 72 wistar rats were divided into 3 groups randomly: sham group (S), ischmia-refusion group (IR), EPO–pretreated group(IR+EPO). In group S , the rats only had a thoracotomy.In group IR, one milliliter of saline solution was administered intraperitoneally 2 h prior to operation.then their right lungs underwent 45 min ischemia, followed by 60 min and 120 min of reperfusion. In group (IR+EPO), EPO was injected intraperitoneally 3000 U/kg 2 h prior to operation, the following experimental protocol was the same as that of the group IR . The rats were anesthetized by intraperitoneal injection of 3% pentobarbital 50 mg/kg body weight. The animals were placed supinely, and a cannula was inserted into the trachea through a midline neck incision. Then the rats were ventilated on a positive pressure espirator.Respiratory rate 60/min, and I:E ratio 1:2,cut open the right ribs to expose right lung lobes.Then, Heparin 100U /kg were injected through the caudal vein. The right pulmonary hilus, including the right main bronchus, artery, and vein was occluded with sutures. After the ischemia period maintained for 45 min, the sutures was removed and the right lung was ventilated and reperfused up to 60min or 120min with ventilation parameters same as initial. At three time spots (45 min ischemia, 60 min and 120 min reperfusion), plasma sample and the whole right lung were collected from the rats in the groups , lung histopathological changes were observed,lung tissue wet/dry ratio, FKN and MCP-1content were determined also.Results 1.FKN: the expression of FKN in group S was limited,groupIR was increased significantly , the contents in group (IR + EPO) were lower than group IR (P<0.05), in group IR were higher than group S(P<0.05) . 2. MCP-1:compared with group S,the content of MCP-1 increased sharply in group IR at each the same time spot (P<0.05);at 120 min reperfusion spot,the content in group (IR + EPO) reduced significantly (P<0.05). 3.W/D raio :there was no significant differences among the three time spots in group S. the W/D raios in group IR were higher than group (IR + EPO) .4 .Histological evaluation: in the process of ischemia-reperfusion, the lung injury was aggravating progressively in groupIR,there was marked pulmonary capillary congestion, interstitial edema occurred with massive infiltration of the inflammatory cell,and the alveolar space was filled with transudate .the degree of injury in group (IR + EPO)was lower than group IR.Conclusions: 1. when pretreated with EPO,the contents of FKN and MCP-1 were significantly reduced. 2. the lung ischemia-reperfusion injury were ameliorated by EPO pretreatment .
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