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

Objective 　To explore the changes of local and systemic coagulation function, especially natural anti-coagulation 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 1h, 6h, 24h and 48h 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, Ca2+; 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 6h 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 6h of SI (P=0.042). FⅤ decreased significantly 1h after SI (P<0.001). The level of TM in BALF decreased significantly 1h after SI (P<0.001), and then recovered gradually 1h later, showing an obvious negative correlation with the severity of lung injury. The activity of ATⅢ and protein C in peripheral blood reduced significantly 1h after SI (P=0.007 and P=0.032, respectively), and the activity of protein C dropped to minimum at 6h of SI. The level of TM in plasma increased gradually after SI, showed significant difference at 6h of SI (P=0.012), and continued to rise after 24h. The level of FⅤ in plasma decreased continuously after SI, while the activity of FⅧ declined significantly 1h after SI (P=0.049). The level of Ca2+ in circulation decreased gradually after SI, declined to minimum at 24h, 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 1h after SI (P=0.004) and then declined to normal level gradually. FIB increased gradually after SI and presented significant difference 24h 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. DOI: 10.11855/j.issn.0577-7402.2018.09.02