人骨髓间充质干细胞对高氧暴露新生大鼠肺组织晚期糖基化终末产物受体通路的影响

Influence of human mesenchymal stem cells on hyperoxia-exposed newborn rats by RAGE-NF-KBsignaling in lung

目的探讨晚期糖基化终末产物受体（RAGE）通路在高氧引致新生大鼠肺组织损伤过程中的表达及人骨髓间充质干细胞对其影响。方法24只新生大鼠依据是否高浓度氧暴露随机分为3组：正常对照组（空气环境下暴露7d）、高氧对照组（95％氧暴露7d＋尾静脉注射PBS）、高氧干预组（95％氧暴露7d＋尾静脉注射hMSC5×10^4）；10日龄处死全部大鼠，光镜观察并盲法评分比较肺组织病理学评分；RT-PCR法检测肺组织匀浆RAGEmRNA、NF-κBmRNA表达；Westernblot检测肺组织匀浆RAGE、NF-κB蛋白表达；ELASA检测肺泡灌洗液（BAL）中TNF-d及sRAGE水平；免疫组化法检测肺组织RAGE表达情况。结果与正常对照组相比，高氧对照组及高氧干预组肺组织损伤评分增加（F=51．59，P=0．000）；RAGEmRNA及蛋白（F=37．21，P=0．000；F=15．88，P=0．000）、NF—κBmRNA及蛋白（F=5．695，P=0．011；F=4．223，P=0．0288）、BALF中TNF-α（F=38．29，P=0．000）均增高，而BALF中sRAGE下降（F=4．804，P=0．0191）。高氧对照组与高氧十预组问差异也有统计学意义（均P〈0．05）。但3组间血清TNF-α、sRAGE等差异均无统计学意义。结论人骨髓问充质干细胞可能通过下调RAGE-NF-κB信号通路对高氧肺损伤发挥保护作用。

Objective To investigate the influence of high oxygen exposure on signaling pathway of the receptor for advanced glycation end products （RAGE）-NF-KB of lung in newborn rats and the mechanisms of protecting lung injury for human mesenchymal stem cells （hMSC）. Methods Twenty-four newborn Sprague-Dawley rats from three litters were randomly divided into three groups, as hyperoxia exposed ＋ hMSC group （group A）, hyperoxia exposed group （group B）, and air-exposed group （group C）. The rats from the group A and B were placed in a sealed Plexiglas chamber with a minimal in-and outflow, providing six to seven exchanges per hour of the chamber volume and maintaining 02 levels above 95%, while rats in the group C only exposed to air simultaneously. Seven days later, rats in the group A were injected intravenously with hMSC （5 × 104） after hyperoxia exposure, but rats in group B and C received subcutaneous injection with PBS alone at the same time point. Then all the rats were exposed to air, and were sacrificed three days later. Immunohistochemistry was used to evaluate the expression of RAGE inhmg tissue. The levels of TNF-α and sRAGE in bronchoalveolar lavage fluid （BALF） and in serum were detected by ELASA, RAGE mRNA and NF-KB mRNA in tissue homogenates were detected by RT-PCR, RAGE and NF-KB by Western blotting; also the value of lung damage score were calculated with histology under light microscope. Results There were significant differences among three groups in the fields of lung damage score （ F = 51.59, P = O. 000）, mRNA and protein of RAGE （ F = 37.21, P = O. 000 ; F = 15.88, P = 0. 000） and NF-KB （ F = 5. 695, P = 0. 011 ; F = 4. 223, P = 0. 0288 ） in lung tissue homogenates, and the level of TNF-cd F = 38.29,P = 0. 000）in BALF, all these parameters in group A and group B were higher than that in group C. While sRAGE in BALF in group A and group B were less than that in group C （F=4. 804, P =0. 0191 ）. There were also significant differences between group A and group B in these parameters（ P 〈 O. 05 ）. There were also no significant differences neither in TNF-α nor in sRAGE in serum among three groups. Conclusions hMSC protects hyperoxia-induced lung injury via downregulating the signaling pathway of RAGE-NF-KB.