Objective: To evaluate effect the of thrombolytic (urokinase, UK) and anticoagulant agent (low-molecular-weight heparin, LMWH) on the pulmonary injury of rabbits with acute pulmonary embolism (PE) by assaying monocyte chemoattractant protein-1 (MCP-1).
Methods: Rabbit models with PE were established by transfusing autologous blood clots on 60 healthy male Japanese white rabbits. Experimental PE rabbits were randomly divided into 3 groups:normal saline (NS) group (n = 18) , LMWH group (n = 18) and UK group (n = 18), and other 18 rabbits underwent sham operations as SHAM group (n = 18). Each group was divided into 3 subgroups based on 2 days (day 2), 4 days (day 4), and 14 days (day 14) after therapies. Arterial blood gas analysis was measured. MCP-1 levels in lung tissue and blood were assayed with ELISA at various times (day 2, day 4 and day 14 ). Fixed sections were stained with trichrome for intimal hyperplasia determination.
Results: The overall rate of success for making PE rabbit models was 90% (54/60), which was not affected by treatment. Compared with NS group, P(A-a)O2 significantly decreased in UK group. Compared with NS group, MCP-1 levels in lung tissue significantly decreased in LMWH group on day 4 [(33 ± 9) ng/L vs (48 ± 5) ng/L, P < 0.05] and day 14 [(30 ± 11) ng/L vs (41 ± 4) ng/L, P < 0.05]; MCP-1 levels in serum on day 14 also significantly decreased in LMWH group [(36 ± 10) ng/L vs (51 ± 5) ng/L, P < 0.05]. Compared with NS group, MCP-1 levels in lung tissue significantly decreased in UK group on day 2 and 4 [Day 2: (34 ± 8) ng/L vs (50 ± 4) ng/L, P < 0.05; Day 4: (29 ± 7) ng/L vs (48 ± 5) ng/L, P < 0.05]; MCP-1 levels in serum on day 2 and day 4 also significantly decreased in UK group [Day 2: (44 ± 3) ng/L vs (48 ± 3) ng/L, P < 0.05; Day 4: (44 ± 4) ng/L vs (53 ± 1)ng/L, P < 0.05].
Conclusions: UK treatment may rapidly improve V/Q ratio and decrease MCP-1 levels in lung tissue or serum, but it can not inhibit persistent inflammation. LMWH can decrease MCP-1 levels in lung tissue or serum, and inhibit persistent inflammation and late intimal hyperplasia.