急性烟雾吸入性肺损伤对大鼠凝血系统的影响

Effect of acute smoke inhalation induced lung injury on coagulation system of rats

目的观察急性吸入大量烟雾后大鼠局部及全身凝血功能,尤其是天然抗凝途径的变化情况。方法建立控温烟雾吸入肺损伤平台,以SD大鼠作为研究对象。对照组及实验组大鼠于烟雾干预后1、6、24、48h收集外周血、肺泡灌洗液(BALF)及肺组织。检测指标包括:肺损伤评分,BALF中血栓调节蛋白(TM)、抗凝血酶Ⅲ(ATⅢ)、凝血因子Ⅱ(FⅡ)、凝血因子Ⅴ(FⅤ)、凝血酶-抗凝血酶复合物(TAT-c)含量,全身凝血指标中的凝血酶原时间(PT)、国际标准化比率(INR)、部分凝血活酶时间(APTT)、纤维蛋白原(FIB),促凝途径中的FⅡ、FⅤ、FⅧ、Ca2+,天然抗凝途径中的TM含量、蛋白C活性、ATⅢ活性等。结果 BALF中FⅡ于烟雾吸入后逐渐降低,6h后明显低于对照组(P=0.039);ATⅢ与对照组比较无明显差异;TAT-c逐渐升高,6h后明显高于对照组(P=0.042)。BALF中TM在烟雾吸入后1h明显降低(P<0.001),1h后逐渐开始恢复,与肺损伤严重程度呈显著负相关。外周血中天然抗凝途径中的ATⅢ活性于1h内明显降低(P=0.007);蛋白C活性于烟雾吸入后1h内明显下降(P=0.032),6h降至最低;可溶性TM含量于烟雾吸入后缓慢升高,6h后明显高于对照组(P=0.012),此后持续升高;促凝途径中的FⅤ水平于烟雾吸入后持续降低;FⅧ活性于烟雾吸入后6h明显降低(P=0.049);循环中Ca2+于烟雾吸入后表现为逐渐降低的趋势,24h明显低于对照组(P=0.043),此后逐渐恢复正常;凝血酶原FⅡ烟雾吸入前后无明显差异;全身凝血检测中,PT、INR烟雾吸入前后无明显差异,APTT于烟雾吸入1h明显升高(P=0.004),此后逐渐恢复;FIB于烟雾吸入后逐渐升高,24h明显高于对照组(P<0.001),此后逐渐降至正常。结论重度烟雾吸入导致肺损伤时,肺部局部表现为促凝为主的凝血功能紊乱,虽然临床总体凝血检测未见明显变化,但存在以促凝途径和抗凝途径主要因子均迅速且显著消耗的凝血功能异常。此外,BALF中TM的变化可用于评估肺损伤的严重程度。

Objective To explore the changes of local and systemic coagulation function, especially natural anticoagulation pathway induced by acute inhalation of heavy smoke. Methods The smoke inhalation platform was established and male SD rats were chosen as study subjects. Blood, bronchoalveolar lavage fluid（BALF） and lung tissues were collected 1 h, 6 h, 24 h and 48 h after smoke interference. The measured parameters included the lung injury score, thrombomodulin（TM）, antithrombin Ⅲ（ATⅢ）, blood coagulation factor Ⅱ（FⅡ） and Ⅴ（FⅤ）, and thrombin-antithrombin complex（TAT-c） in BALF; the global coagulation parameters included prothrombin time（PT）, international normalized ratio（INR）, activated partial thromboplastin time（APTT）, fibrinogen（FIB）, platelets in circulation;the pro-coagulation factors included FⅡ, FⅤ, FⅧ, Ca^2＋; and the natural anti-coagulation factors included TM, protein C activity and ATⅢ activity. Results The levels of FⅡ decreased gradually after smoke inhalation（SI）, and showed significant difference at 6 h of SI（P=0.039）. The level of ATⅢ showed no significant difference between control and SI groups before and after SI, while of TAT-c in BALF increased significantly at 6 h of SI（P=0.042）. FⅤdecreased significantly 1 h after SI（P〈0.001）. The level of TM in BALF decreased significantly 1 h after SI（P〈0.001）, and then recovered gradually 1 h later, showing an obvious negative correlation with the severity of lung injury. The activity of ATⅢ and protein C in peripheral blood reduced significantly 1 h after SI（P=0.007 and P=0.032, respectively）, and the activity of protein C dropped to minimum at 6 h of SI. The level of TM in plasma increased gradually after SI, showed significant difference at 6 h of SI（P=0.012）, and continued to rise after 24 h. The level of FⅤ in plasma decreased continuously after SI, while the activity of FⅧdeclined significantly 1 h after SI（P=0.049）. The level of Ca^2＋ in circulation decreased gradually after SI, declined to minimum at 24 h, and then recovered gradually afterwards. Plasma level of prothrombin（FⅡ） showed no significant difference before and after SI. In global coagulation tests, PT and INR showed no significant difference between different groups, APTT significantly increased 1 h after SI（P=0.004） and then declined to normal level gradually. FIB increased gradually after SI and presented significant difference 24 h after SI（P〈0.001）, and then declined to normal afterwards. Conclusions Lung injury induced by severe smoke inhalation mainly presents an abnormal coagulation status, where both systemic pro-and anti-coagulation systems are stimulated, and the majority of pro-and anti-coagulation factors, such as TM, ATⅢ, FⅡ, FⅤ and FⅧ, are consumed rapidly and markedly. In addition, the changes of TM in BALF may be used to evaluate the severity of pulmonary injury.