重组人促红细胞生成素对脓毒症大鼠肺脏的保护作用

Protective effects of recombinant human erythropoietin on acute lung injury induced by sepsis in rats

目的探讨重组人促红细胞生成素（recombinant human erythropoietin，rHuEPO）对内毒素所致大鼠脓毒症急性肺损伤的保护作用。方法45只雄性SD大鼠随机（随机数字法）分为对照组、模型组、rHuEPO组，每组均15只。经静脉推注脂多糖LPS（6mg／kg）复制急性肺损伤（ALI）的动物模型，rHuEPO组造模前60min静脉推注rHuEPO（5000U／kg），观察12h后处死。留取颈动脉血及肺组织标本。测定氧和指数（OI）、动脉血氧分压（PaO2）、动脉血二氧化碳分压（PaCO2）、pH值。采用酶联免疫法（ELISA法）测定大鼠血清TNF-α、IL-6、iNOS的水平。在光镜和透射电镜下观察肺组织的病理形态学变化，并取右肺下叶计算肺湿／干质量比（W／D）。结果（1）血气分析：与对照组相比，脓毒症组及rHuEPO组大鼠动脉血PaO2、pH显著降低，PaCO2显著升高；与脓毒症组相比，rHuEPO组PaO2、pH显著升高及PaCO2显著降低，差异具有统计学意义（P〈0．05）。（2）各组大鼠肺组织湿干质量比（W／D）变化：与对照组相比，脓毒症组及rHuEPO组肺组织W／D显著增加；与脓毒症组相比，rHuEPO组肺组织W／D显著降低，差异具有统计学意义（P〈0．05）。（3）各组大鼠12h血清TNF-α、IL-6、iNOS水平的变化：脓毒症组及rHuEPO组上述指标明显高于对照组；与脓毒症组相比，rHuEPO组上述指标明显降低，差异具有统计学意义（P〈0．01）。（4）光镜及电镜观察脓毒症组病理学改变为急性弥漫性肺损伤，表现为肺泡腔内出血、渗出、炎性细胞浸润，肺微血管内皮细胞、Ⅰ型和Ⅱ型上皮细胞坏死；rHuEPO组急性肺损伤明显轻于脓毒症组，只可见到局灶性肺泡少量炎性细胞浸润。结论rHuEPO能够降低血清TNF-α、IL-6、iNOS水平进而调节炎症反应，对脓毒症所致急性肺损伤具有一定的保护作用。

Objective To investigate the protective effects of recombinant human erythropoietin （rHuEPO） on acute lung injury （ALI） induced by lipopolysaceharide （LPS）. Methods Fourty-five rats were randomly （random number） assigned to three groups, namely control group, model group, and rHuEPO group. ALI was induced by intravenous injection of LPS （6 mg/kg）. The rHuEPO （5000 U/kg） was injected intravenously into rats 60 min before LPS challenge. The general status of rats was observed. Twelve hours after modeling, the rats were sacrificed and the tissue samples including lung tissue and blood were collected. PaO2, PaCO2, pH, the lung wet/dry weight ratio, plasma cytokines [ interleukin （IL） IL-6 and tumor necrosis factor-alpha （ TNF-α ） ], and inducible nitric oxide synthase （ iNOS ） were detected. Cytokines were assayed with ELISA method. Pathological changes of lung tissues were observed under light microscope and transmission electron microscopy. Results （ 1 ） Compared with the control group, PaO2 , pHin the model group and in the rHuEPO group were significantly lower （ P 〈 0. 05 ） , and PaCO2 were significantly higher （P 〈 0. 05 ）. Compared with the model group, PaO2, pH in the rHuEPO group were significantly higher （ P 〈 0. 05 ）, and PaCO2 were significantly lower （ P 〈 0. 05 ）. （ 2 ） Compared with the eontrol group, the W/D weight ratio of lung tissues in the model group and the rHuEPO group was significantly higher （ P 〈 0. 05）. Compared with the model group, the W/D weight ratio of lung tissues in the rHuEPO group signifieantly lower （P 〈 0. 05 ）. （ 3 ） The levels of TNF-α, IL-6 and iNOS in serum of rats in the control group were lower than those in the model group and the rHuEPO group （ P 〈 0. 01 ）. The serum levels of TNF-c~, IL-6 and iNOS of rats in the rHuEPO group were significantly lower compared with the model group （P 〈 0. 01 ）. （4） The light microscopy and the transmission electron microscopy showed the model group had histopathologic ehanges with acute diffuse lung injury manifested by intra-alveolar hemorrhage, exudate, inflammatory cells infiltration, Ⅰ type and Ⅱ type ePithelial cell necrosis and detachment, and the pathological changes of lung tissue in the rHuEPO group were not as serious as those in the LPS group, showing only a little inflammatory cells infiltration of focal alveoli. Conclusions Recombinant human erythropoietin can inhibit the genesis of TNF-ct, IL-6 and iNOS in serum, modifying the inflammatory response and providing proteetive effects against acute lung injury induced by sepsis.