阻断E-选择素缓解LPS诱导的急性肺损伤
发布时间：2019-01-08 13:54
【摘要】：E-选择素是表达在内皮细胞表面的一种重要的粘附分子。在组织受到损伤或有炎症反应时，它的表达上调。升高的E-选择素水平对血流中的白细胞有强烈的吸引作用，聚集到损伤或炎症部位的白细胞释放各种氧自由基以及炎症因子，对入侵的病原体起到了很好的杀伤作用。但是异常表达的E-选择素以及过度聚集和激活的白细胞往往也会对正常组织产生严重损伤。比如由LPS引起的急性肺损伤的发病就涉及这个过程。在本工作中我们提出假说——如果可以阻断E-选择素这种重要的免疫粘附分子，可以对急性肺损伤起到显著的保护作用。 我们使用LPS作为炎症刺激剂在小鼠上复制急性肺损伤的模型，实验对象是E-选择素基因敲除鼠以及野生型对照小鼠。E-选择素基因敲除小鼠在造模后的状态明显好于野生型对照组。12小时后，用红外照相机记录各组小鼠的皮肤表面温度。随后，，取小鼠血样，肺组织样本，肺泡灌洗液等样本做进一步检测：E-选择素和髓过氧化物酶(MPO)蛋白在肺组织中的表达，肺组织丙二醛(MDA)含量，血清炎症因子水平，肺组织干湿比(wet/dry),病理学染色等等。结果发现LPS造模后，E-选择素基因敲除小鼠的血清炎症因子TNF-α、IL-1β明显低于野生型对照小鼠，肺泡灌洗液里的白细胞聚集也明显较少，MPO蛋白的表达更少，MDA含量更低，体温更接近正常。另外生存率实验表明，LPS作用后的E-选择素基因敲除小鼠的生存率明显优于野生型小鼠的造模对照。 随后我们希望可以通过体外筛选可以找到有效的E-选择素抑制剂。LPS刺激人脐静脉内皮细胞(HUVEC)可以明显上调E-选择素的表达，但是100uM的西咪替丁在不影响细胞活力的情况下，对E选择素的表达有显著的抑制作用。 进一步的实验发现，小鼠口服西咪替丁(200mg/kg)，可以明显改善LPS诱导的急性肺损伤。在造模后的12小时，红外成像系统表明小鼠的体温更接近正常，肺水肿(干湿比)指数明显低于模型对照组，血清炎症因子TNF-α更低，生存率也明显延长。 我们得出结论：阻断E选择素可以缓解LPS诱导的急性肺损伤，西咪替丁的保护作用很可能与它抑制E-选择素的效应有关。
[Abstract]:E-selectin is an important adhesion molecule expressed on endothelial cell surface. Its expression is up-regulated when the tissue is damaged or has an inflammatory response. The elevated level of E- selectin has a strong attraction to the white blood cells in the blood stream. The white blood cells gathered in the injured or inflammatory sites release various oxygen free radicals and inflammatory factors, which can kill the invading pathogens. However, abnormal expression of E-selectin and excessive aggregation and activation of white blood cells can also cause severe damage to normal tissues. For example, acute lung injury caused by LPS is involved in this process. In this work, we hypothesized that if E- selectin, an important immune adhesion molecule, could be blocked, it could play a significant protective role in acute lung injury. We used LPS as an inflammatory stimulant to model acute lung injury in mice. Eselectin gene knockout mice and wild type control mice were studied. The status of Eselectin gene knockout mice was significantly better than that of wild type control mice after 12 hours. The skin surface temperature of each group was recorded by infrared camera. Then, the blood samples, lung tissue samples and alveolar lavage fluid samples of mice were taken for further detection: the expression of E- selectin and myeloperoxidase (MPO) protein in lung tissue, the content of malondialdehyde (MDA) in lung tissue, the level of serum inflammatory factor, and so on. Lung tissue dry-wet ratio (wet/dry), pathological staining and so on. The results showed that the levels of serum inflammatory cytokines TNF- 伪 and IL-1 尾 in E- selectin gene knockout mice were significantly lower than those in wild type control mice, and the leukocyte aggregation in alveolar lavage fluid was significantly lower, and the expression of MPO protein was less in E- selectin gene knockout mice. MDA levels are lower and body temperature is closer to normal. In addition, the survival rate of E- selectin gene knockout mice treated with LPS was significantly better than that of wild-type mice. Then we hope that we can find an effective inhibitor of E- selectin through in vitro screening. (HUVEC) stimulated by LPS can significantly up-regulate the expression of E- selectin in human umbilical vein endothelial cells. But cimetidine of 100uM inhibited the expression of E-selectin without affecting cell viability. Further experiments showed that cimetidine (200mg/kg) could significantly improve acute lung injury induced by LPS in mice. After 12 hours, the infrared imaging system showed that the body temperature of the mice was closer to normal, the index of pulmonary edema (dry-wet ratio) was significantly lower than that of the model control group, the serum inflammatory factor TNF- 伪 was lower, and the survival rate was longer. We conclude that blocking E-selectin can alleviate acute lung injury induced by LPS and the protective effect of cimetidine may be related to its inhibitory effect on Eselectin.
【学位授予单位】：第二军医大学
【学位级别】：博士
【学位授予年份】：2012
【分类号】：R563.8
本文编号：2404692
[Abstract]:E-selectin is an important adhesion molecule expressed on endothelial cell surface. Its expression is up-regulated when the tissue is damaged or has an inflammatory response. The elevated level of E- selectin has a strong attraction to the white blood cells in the blood stream. The white blood cells gathered in the injured or inflammatory sites release various oxygen free radicals and inflammatory factors, which can kill the invading pathogens. However, abnormal expression of E-selectin and excessive aggregation and activation of white blood cells can also cause severe damage to normal tissues. For example, acute lung injury caused by LPS is involved in this process. In this work, we hypothesized that if E- selectin, an important immune adhesion molecule, could be blocked, it could play a significant protective role in acute lung injury. We used LPS as an inflammatory stimulant to model acute lung injury in mice. Eselectin gene knockout mice and wild type control mice were studied. The status of Eselectin gene knockout mice was significantly better than that of wild type control mice after 12 hours. The skin surface temperature of each group was recorded by infrared camera. Then, the blood samples, lung tissue samples and alveolar lavage fluid samples of mice were taken for further detection: the expression of E- selectin and myeloperoxidase (MPO) protein in lung tissue, the content of malondialdehyde (MDA) in lung tissue, the level of serum inflammatory factor, and so on. Lung tissue dry-wet ratio (wet/dry), pathological staining and so on. The results showed that the levels of serum inflammatory cytokines TNF- 伪 and IL-1 尾 in E- selectin gene knockout mice were significantly lower than those in wild type control mice, and the leukocyte aggregation in alveolar lavage fluid was significantly lower, and the expression of MPO protein was less in E- selectin gene knockout mice. MDA levels are lower and body temperature is closer to normal. In addition, the survival rate of E- selectin gene knockout mice treated with LPS was significantly better than that of wild-type mice. Then we hope that we can find an effective inhibitor of E- selectin through in vitro screening. (HUVEC) stimulated by LPS can significantly up-regulate the expression of E- selectin in human umbilical vein endothelial cells. But cimetidine of 100uM inhibited the expression of E-selectin without affecting cell viability. Further experiments showed that cimetidine (200mg/kg) could significantly improve acute lung injury induced by LPS in mice. After 12 hours, the infrared imaging system showed that the body temperature of the mice was closer to normal, the index of pulmonary edema (dry-wet ratio) was significantly lower than that of the model control group, the serum inflammatory factor TNF- 伪 was lower, and the survival rate was longer. We conclude that blocking E-selectin can alleviate acute lung injury induced by LPS and the protective effect of cimetidine may be related to its inhibitory effect on Eselectin.
【学位授予单位】：第二军医大学
【学位级别】：博士
【学位授予年份】：2012
【分类号】：R563.8
【共引文献】
相关期刊论文 前1条
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