肝素及其降解片段对急性呼吸窘迫综合征细胞外组蛋白拮抗作用的比较

The comparison of heparan sulfate and its fragments on the protection against extracellular histones during the pathogenesis of acute respiratory distress syndrome

目的比较肝素（heparan sulfate，HS）及其片段在大鼠急性呼吸窘迫综合征（acute respiratory distress syndrome, ARDS）发病中对细胞外组蛋白的拮抗作用，研究肝素降解在炎症发展中的作用。方法实验设对照组、CTH损伤组、肝素片段dp4、dp10组和肝素干预组，每组6只大鼠。CTH损伤组经股静脉注射小牛胸腺组蛋白（calf thymus histone，CTH）复制大鼠ARDS模型，对照组给予等量生理盐水。干预组经腹腔注射给予肝素或肝素片段（10 mg/kg，每6 h 1次，24 h）进行干预。检测肺湿/干重比值、支气管肺泡灌洗液（bronchoalveolar lavage fluid，BALF）中蛋白含量、白细胞数量，光学显微镜下观察中性粒细胞数量、肺组织病理的改变。结果CTH损伤组大鼠的肺湿/干重比值、BALF中蛋白浓度、白细胞和中性粒细胞数量均明显高于对照组，差异有统计学意义（P〈0.01）。肝素干预组肺湿/干重比值、BALF中蛋白浓度、白细胞和中性粒细胞数量均明显低于CTH损伤组，差异有统计学意义（P〈0.05）。肝素片段dp10干预组BALF中蛋白浓度和BALF中白细胞数量明显低于CTH损伤组，差异有统计学意义（P〈0.05）。dp10干预组的肺湿/干重比值、BALF中中性粒细胞数量均低于CTH损伤组，差异均无统计学意义（P〉0.05）。肝素片段dp4干预组肺湿/干重比值、BALF中蛋白浓度、白细胞数量和中性粒细胞数量低于CTH损伤组，差异均无统计学意义（P〉0.05）。光学显微镜下可见CTH损伤组大鼠的肺组织出血、水肿、肺泡间质增厚，肺泡中弥漫分布炎症细胞。肝素片段和肝素干预组的肺组织病变程度要比CTH损伤组明显改善,而且肝素干预组的肺组织损伤程度轻于肝素片段干预组。结论肝素和肝素片段对CTH导致的肺损伤具均有防护效果，肝素全长优于肝素片段。

ObjectiveIn order to explore the role of heparan sulfate （HS） during the pathogenesis of acute respiratory distress syndrome （ARDS） , the protective effect of HS and its fragments against extracellular histones was compared.MethodsCalf thymus histones （CTH） were injected via femoral vein to induce ARDS in rats. HS, HS fragments or saline was intraperitoneally injected （10mg/kg, Q6h, 24h） to test the protective effect against CTH. The ratio of wet/dry lung weight, protein content in bronchoalveolar lavage fluid （BALF） , total leukocyte and neutrophil count in BALF were measured.ResultsAfter CTH injection, the ratio of wet/dry lung weight （5.7±0.95） was much higher than the saline control group （3.1±0.15）. The protein content （0.47±0.086mg/ml） , total leukocyte[ （97.4±15.6l） ×10^4/ml] and neutrophil （18±3.4/LPF） in BALF were obviously increased compared with the saline control group. The intervention of HS evidently decreased ratio of wet/dry lung weight （4.2±0.41） , protein content[ （0.26±0.019） mg/ml], leukocyte[ （61.3±5.74） ×10^4/ml] and neutrophil （12±1.8/LPF） in BALF. HS fragments also decreased ratio of wet/dry lung weight, protein content, leukocyte and neutrophil count in BALF though the strength was much less than HS.ConclusionHS and its fragments could provide protection against extracellular histones during the pathogenesis of ARDS. For the protective effect full length HS was much better than HS fragments.