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目的观察外源性促红细胞生成素(EPO)对高体积分数氧(高氧)肺损伤中单核细胞趋化蛋白-1(MCP-1)表达的影响,探讨外源性EPO对高氧肺损伤的干预作用。方法将96只出生12h内新生大鼠随机分为4组。Ⅰ组:空气对照;Ⅱ组:空气+重组人促红细胞生成素(rhEPO);Ⅲ组:高氧对照;Ⅳ组:高氧+rhEPO。Ⅲ组、Ⅳ组新生大鼠高氧暴露(吸氧体积分数850mL·L-1),Ⅱ组、Ⅳ组于出生0d和2d予rhEPO1200IU·kg-1背部皮下注射,Ⅰ组、Ⅲ组予等量9g·L-1盐水注射。在实验3d、7d和14d每组随机选取8只处死,取其肺组织,采用HE染色观察其肺组织病理改变,生化法检测其肺组织髓过氧化物酶(MPO)水平;免疫组织化学和Western blotting法检测其肺组织MCP-1蛋白的变化。结果Ⅲ组新生大鼠出生3d时肺组织可见炎症反应,7d时最为显著,14d时肺泡结构简化,间质呈不同程度纤维化。Ⅳ组新生大鼠出生7d时炎性渗出和浸润较Ⅲ组减轻,14d时肺泡发育改善。Ⅳ组各时点MPO水平较Ⅲ组明显降低[(0.58±0.06)U·L-1vs(0.68±0.08)U·L-1,P<0.05;(0.77±0.06)U·L-1vs(1.09±0.14)U·L-1,P<0.001;(0.66±0.43)U·L-1vs(0.74±0.05)U·L-1,P<0.05]。MCP-1在Ⅲ组表达增强,7d时达峰值(P<0.001);Ⅳ组MCP-1表达较Ⅲ组减弱[(21.64±3.65)vs(28.98±3.66),P<0.01;(41.41±6.21)vs(95.69±6.96),P<0.001;(30.21±3.48)vs(43.98±5.29),P<0.001]。Ⅰ组、Ⅲ组、Ⅳ组各时点MCP-1蛋白变化与肺组织MPO水平呈正相关(r=0.538,P<0.01;r=0.906,P<0.001;r=0.800,P<0.001)。结论EPO可减轻高氧导致的肺组织炎性损伤,最终改善肺发育,EPO抗炎作用机制与其抑制趋化因子MCP-1表达有关。
Objective To investigate the effect of exogenous erythropoietin (EPO) on the expression of monocyte chemotactic protein-1 (MCP-1) in high volume fraction oxygen (hyperoxia) Injury intervention. Methods 96 newborn rats were randomly divided into 4 groups within 12h after birth. Group Ⅰ: Air control; Group Ⅱ: Air + recombinant human erythropoietin (rhEPO); Group Ⅲ: hyperoxia control; Group Ⅳ: hyperoxia + rhEPO. Rats in group Ⅲ and group Ⅳ were exposed to hyperoxia (850 mL·L -1). Groups Ⅱ and Ⅳ were injected subcutaneously with rhEPO at 1,200 IU · kg -1 on days 0 and 2 of birth, Amount of 9g · L-1 saline injection. Eight rabbits were randomly selected from each group on the 3rd, 7th and 14th day of the experiment, and their lung tissues were taken out. The pathological changes of the lung tissues were observed by HE staining. The levels of myeloperoxidase (MPO) The changes of MCP-1 protein in lung tissue were detected by Western blotting. Results Inflammatory reaction was observed in the lung tissue of neonatal rats in group Ⅲ at 3 days after birth, most notably at 7 days. The alveolar structure was simplified on the 14th day and fibrosis was observed at different degrees in the interstitium. Inflammatory exudation and infiltration of neonatal rats in group Ⅳ were less than those in group Ⅲ on the 7th day of birth, and the development of alveoli was improved on the 14th day. The level of MPO in group Ⅳ was significantly lower than that in group Ⅲ [(0.58 ± 0.06) U · L-1vs (0.68 ± 0.08) U · L-1, P <0.05, (0.77 ± 0.06) U · L -1vs ± 0.14) U · L-1, P <0.001; (0.66 ± 0.43) U · L-1vs (0.74 ± 0.05) U · L-1, P <0.05]. The expression of MCP-1 in group Ⅲ was higher than that in group Ⅲ (P <0.001), and the expression of MCP-1 in group Ⅳ was significantly lower than that in group Ⅲ [(21.64 ± 3.65) vs (28.98 ± 3.66), P <0.01; (41.41 ± 6.21 ) vs (95.69 ± 6.96), P <0.001; (30.21 ± 3.48) vs (43.98 ± 5.29), P <0.001]. The changes of MCP-1 protein at each time point in group Ⅰ, Ⅲ and Ⅳ were positively correlated with the level of MPO in lung tissue (r = 0.538, P <0.01; r = 0.906, P <0.001; r = 0.800, P <0.001). Conclusion EPO can reduce the inflammatory injury induced by hyperoxia and finally improve the lung development. The anti-inflammatory mechanism of EPO is related to the inhibition of chemokine MCP-1 expression.