[The low molecular weight heparin on rat pulmonary surfactant associated protein A of acute pulmonary embolism].

OBJECTIVE: To explore the effect of low molecular weight heparin (LMWH) on the changes of pulmonary surfactant associated protein A (SPA) of rats in acute pulmonary embolism. METHODS: Male SD rats were injected with medical gelfoam microspheres via jugular vein to induce PE model. Rats were randomized into three groups: control group (n = 8), embolism for 2 weeks group (n = 8) and LMWH therapy group (n = 8); The LMWH therapy group were injected Nadroparin subcutaneously immediately after operation, 0.1 ml/10 kg, once every 12 h. Saline were injected into the control group instead of gelfoam granule solution without further procedure. All the rats were sacrificed at the time of 2 weeks. Pulmonary artery pressure were detected by right heart catheterization and artery blood gas were analyzed at the time of sacrifice. Lung tissue were sliced and dyed with HE to observe the embolism of pulmonary artery. Methods of RT-PCR and western blot were used to study the changes of SPA mRNA and SPA protein in lung tissue. RESULTS: In control group, embolism group and LMWH group, the pulmonary pressure were (14.2 +/- 4.1) mm Hg, (29.0 +/- 8.2) mm Hg, (25.50 +/- 2.74) mm Hg respectively (F3.01, P < 0.05); the artery oxygen blood pressure (PaO2) were (94.1 +/- 8.8) mm Hg, (73.4 +/- 14.3) mm Hg, (82.86 +/- 3.73) mm Hg respectively (F 1.31, P < 0.05); SPA mRNA in three groups were 1.43 +/- 0.51, 0.87 +/- 0.35, 1.07 +/- 0.20 respectively (F 2.87, P < 0.05); and SPA protein were 1.00 +/- 0.00, 0.52 +/- 0.32, 0.90 +/- 0.22 respectively (F 2.96, P < 0.05); Under microscope, lung tissue were seen congestion, edema, infiltration of inflammatory cells in embolism group, which were lessened in LMWH group. CONCLUSIONS: The lung SPA decrease significantly in acute pulmonary embolism, and LMWH can increase the SPA, which may be one of mechanisms of LMWH in treatment of pulmonary embolism.