不同剂量促红细胞生成素对大鼠肺缺血再灌注损伤的保护作用

Protective effects of different doses of erythropoietin on lung ischemia-reperfusion injury in rats

目的探讨不同剂量促红细胞生成素在大鼠肺缺血再灌注时对单核细胞趋化蛋白(MCP)-1表达的影响,研究大鼠肺缺血再灌注损伤的机制。方法将85只健康的雄性Wistar大鼠随机分为5组(n=17):缺血再灌注组(I/R),促红细胞生成素低剂量组(L组)、中剂量组(M组)、高剂量组(H组),假手术组(S组)。缺血前24 h,L、M、H组分别腹腔注射重组促红细胞生成素1 000、3 000和5 000 U/kg,I/R组注射生理盐水;该4组予以阻断左侧肺门部血流60 min,再灌注90 min后(S组只开胸不阻断左肺门),处死大鼠,取左肺标本,观察各组中肺脏颜色、有无出血点等,测动脉血气分析,测量肺的湿干重比(W/D),制作石蜡切片,苏木精-伊红(HE)染色电镜下观察肺组织病理变化,免疫组化染色检测肺组织中MCP-1的含量。结果与S组比较,缺血再灌注各组肺组织MCP-1表达水平和W/D值均上升(P均<0.01),动脉血Pa O2值下降(P均<0.01),且均以I/R组明显;促红细胞生成素不同剂量组间比较,M组肺组织MCP-1表达水平较L、H组降低(P均<0.05),W/D值较L、H组降低(P均<0.05),动脉血Pa O2值较L、H组上升(P均<0.05)。结论不同剂量促红细胞生成素对大鼠肺缺血再灌注损伤保护作用不同,保护作用最佳剂量为3 000 U/kg,该保护作用可能是通过抑制MCP-1介导的过度炎症反应来实现的。

Objective To study the effect of different doses of erythropoietin（ EPO） on expression of monocyte chemotactic protein-1（ MCP-1） when lung ischemia-reperfusion injury and explore the mechanism of lung ischemia-reperfusion injury in rats. Methods Eighty-five healthy male Wistar rats were randomly divided into five groups（ n = 17 each） ： ischemiareperfusion group（ I / R group）,low dose-EPO group（ L group）,middle dose-EPO group（ M group）,high dose-EPO group（ H group） and sham-operation group（ S group）. At 24-hour before ischemia,human recombinant erythropoietin（ rh EPO）was given by intraperitoneal injection in L,M and H groups（ 1 000,3 000 and 5 000 U / kg,respectively）,and normal saline was given by intraperitoneal injection in I / R group. The ischemia-reperfusion rat model was established by blocking the blood flow of left lung hilum for 60 minutes then reperfusion for 90 minutes in I / R,L,M and H group. No treatment except opening thorax was given in S group. The left lung samples were taken after killing rats. The arterial blood gas analysis was assayed,and the wet / dry weight ratio（ W / D） of the lung was measured. After making paraffin section and haematoxylineosin（ HE） staining,the pathological changes of the lung tissues were observed under electronic microscope. The MCP-1content of lung tissues was assayed by immunohistochemical method. Results Compared with S group,the MCP-1 expression level and the value of W / D increased significantly（ all P〈0. 01）,and the arterial partial pressure of oxygen（ Pa O2）decreased significantly（ all P〈0. 01） in I / R,L,M and H groups especially in I / R group. Compared with L and H groups,the MCP-1 expression level and the value of W / D decreased（ all P〈0. 05）,and Pa O2increased（ all P〈0. 05） in M group. Conclusion The protective effects of different doses of EPO on lung ischemia-reperfusion injury in rats might be different,and the optimal dose is 3 000 U / kg. The protective effect is achieved possibly through inhibiting excessive inflammatory reaction mediated by MCP-1.