高原鼢鼠、高原鼠兔和大鼠肺表面活性物质组成和含量的比较

本研究通过分析肺表面活性物质(pulmonary surfactant,PS)组成和含量探讨高原鼢鼠(Myospalax baileyi)和高原鼠兔(Ochotona curzoniae)的低氧适应机制。高原鼢鼠和高原鼠兔各36只,捕捉于海拔3600 m左右的青海省海南州贵德县拉脊山地区,36只Sprague-Dawley(SD)大鼠购自海拔1500 m左右的兰州大学实验动物中心。所有动物麻醉后通过肺循环进行肺灌洗,充分洗净肺组织中的血液,取出完整的肺组织灌洗得到肺泡灌洗液。应用高效液相色谱法分析三种动物PS中磷脂的组成和含量;应用G-250考马斯亮蓝法、聚丙烯酰胺凝胶电泳(PAGE)和质谱测序分析PS蛋白质的含量和种类;应用溶氧电极测定了PS溶液中的溶氧量。结果表明:高原鼢鼠、高原鼠兔和SD大鼠PS中,总磷脂含量依次显著增加(P<0.05),总蛋白含量依次显著减少(P<0.05);三种动物PS中均含有亚油酰棕榈酰胆碱(linoleic palmitoylphosphatidylcholine,LPPC)、二棕榈酰磷脂酰胆碱(dipalmitoylphosphatidylcholine,DPPC)、磷脂酰甘油(phosphatidylglycerol,PG)、磷脂酰肌醇(phosphatidylinositol,PI)和磷脂酰丝氨酸(phosphatidylserine,PSe)等5种磷脂成分,但其相对含量明显不同;在高原鼢鼠、高原鼠兔和SD大鼠中,LPPC所占比例依次显著增加(P<0.01);高原鼢鼠PS磷脂中,DPPC、PG和PI所占比例极显著高于高原鼠兔(P<0.01),高原鼠兔与SD大鼠之间没有显著差异(P>0.05);高原鼢鼠与高原鼠兔PS磷脂中,PSe所占比例没有显著差异(P>0.05),但均极显著高于SD大鼠(P<0.01)。三种动物PS中均含有血清白蛋白(serum albumin,SA),高原鼢鼠和高原鼠兔PS中含有血红蛋白β亚基构成的含血红素的同源四聚体蛋白,高原鼢鼠和SD大鼠PS中含有免疫球蛋白(immunoglobulin,Ig)重链残基,高原鼢鼠Ig重链残基含量极显著高于SD大鼠(P<0.01),含血红素蛋白含量显著高于高原鼠兔(P<0.05)。高原鼢鼠、高原鼠兔和SD大鼠PS溶液中溶氧量依次显著减小(P<0.01),但均显著高于生理盐水(P<0.01)。以上结果提示,高原鼢鼠和高原鼠兔PS中总蛋白含量显著增加,总磷脂含量显著减少,蛋白成分中含有高含量的含血红素同源四聚体蛋白,且高原鼢鼠主要磷脂成分DPPC的相对含量显著增加,这种PS成分和含量的变化增强了这两种高原动物对低氧环境的适应性。

Comparison of the composition and content of pulmonary surfactant among plateau zokors,plateau pikas and rats

In the present study,the composition and content of pulmonary surfactant(PS)were analyzed to explore the hypoxia adaptation mechanism in plateau zokors(Myospalax baileyi)and plateau pikas(Ochotona curzoniae).36 plateau zokors and plateau pikas were trapped alive at the Laji Mountain in Guide County,Qinghai Province(at the altitude of about 3600 m),and 36 Sprague-Dawley(SD)rats were purchased from the experimental animal center of Lanzhou University(at the altitude of about 1500 m).All animals were lavaged after laboratory anesthesia,the blood in lung tissues was fully washed out and the lung tissues were then taken out to obtain the bronchoalveolar lavage fluid by bronchoalveolar lavage.The composition and content of phospholipids in the PS of three different kinds of animals were analyzed by using high performance liquid chromatography;the protein composition,content and types in the PS were analyzed by G-250 Coomassie brilliant blue method,polyacrylamide gel electrophoresis(PAGE)and mass spectrometry;the dissolved oxygen in the PS solutions were determined by using dissolved oxygen electrode.The results showed that the total contents of phospholipids in the PS were successively increased among plateau zokors,plateau pikas and SD rats(P<0.05),while the total content of proteins successively decreased(P<0.05).There were five phospholipids identified in the PS,including linoleic palmitoylphosphatidylcholine(LPPC),dipalmitoylphosphatidylcholine(DPPC),phosphatidylglyerol(PG),phosphatidylinositol(PI)and phosphatidylserine(PSe),but the relative contents of these phospholipids were different.The relative content of LPPC was successively increased among plateau zokors,plateau pikas and SD rats(P<0.01).The relative contents of DPPC,PG and PI in the PS of plateau zokors were significantly higher than those of plateau pikas(P<0.01),while insignificant differences between plateau pikas and SD rats(P>0.05).The relative content of PSe had no significant differences between plateau zokors and plateau pikas(P>0.05),but both were significantly higher than that of SD rats(P<0.01).The serum albumin(SA)was identified in the PS of three kinds of animals,including homologous tetramer protein containing heme,which is composed of hemoglobinβsubunit,in plateau zokors and plateau pikas.Immunoglobulin(Ig)heavy chain was found in PS of plateau zokors and SD rats.The content of Ig heavy chain in plateau zokor was significantly higher than that in SD rats(P<0.01),and the content of protein containing heme was significantly higher than that in plateau pikas(P<0.05).The amount of dissolved oxygen was successively decreased in the PS among plateau zokors,plateau pikas and SD rats(P<0.01),but it was significantly higher than that in saline(P<0.01).These results suggest that the total content of proteins in the PS of plateau zokors and plateau pikas was significantly higher,while the total content of phospholipids was significantly decreased.There were high content of homologous tetramer protein containing heme in the PS of plateau zokors and plateau pikas.The relative content of DPPC,the main component of phospholipids,was significantly increased in plateau zokors.The changes of PS component and content improve the adaptability of the two plateau animals in hypoxia environment.