| Objective To research the effect and mechanism of Ulinastatin(UTI) on acute lung injury in rabbits induced by blast.Methods The model of acute lung injury in rabbits was induced by blast. According to the randomized table, all the rabbits were randomly divided into 5 group, Normal group (N), ALI group (I) and UTI groups of different doses (L, M, H).When the models of acute lung injury in rabbits induced by blast were finished, the rabbits in group(L, M, H) were intravenously injected with different doses of UTI (2.5,5,10x104 U/kg), while the rabbits in group N and group I were injected with normal saline of same doses. The blood were collected at 4 hours and the bronchial alveolar lavage fluid (BALF), blood and some lung tissues were saved at 24 hours. TNF-a, IL-6, IL-10 were determined by ELISA method. The NF-κB was evaluated by Western blot and the Reverse transcription polymerase chain reaction. The wet to dry weight ratios were determined. The pathological changes of lung tissues were observed under the microscope.Result1. General manifestations:Before the explosion, animals breathe smoothly, all the rabbits act normally. After the explosion, the oral and ear skin of I group animal appeared cyanosis, such as breathing rate is accelerated, the oral or nasal of the animals partly appeared with bubble secretions, with or without respiratory distress, irritability, lungs appeared dry or wet rale, part of the animals even appeared a brief coma. Explosion injury rabbits appeared respiratory insufficiency.2. The levels of lung wet to dry weight ratio (W/D):The levels of W/D in group I, H, M, L were significantly higher than them in group N (P<0.05). Compared with group I, the levels of group H, M, L were lower, and the group H is the most obvious group (P<0.05).3. TNF-a in the Bronchoalveolar lavage fluid (BALF):Compared with group N, the levels of TNF-a in other groups in BALF were higher constantly (P<0.05). With the treatment of UTI, the values of TNF-a were lower than their measures in group I (P<0.05). The levels of TNF-a were lower obviously than other groups, especially in comparison with group I, M, L (P<0.05). Compared with group L,the levels in groups M were lower somewhat, but it had no statistic differences (P>0.05)4. IL-6 in the Bronchoalveolar lavage fluid (BALF):Compared with group N, the levels of IL-6 in other groups in BALF were higher constantly (P<0.05). The levels of IL-6 were lower obviously than other groups, especially in comparison with group I, M, L (P<0.05), and the group H is the most obvious group (P<0.05).5. IL-10 in the Bronchoalveolar lavage fluid (BALF):Compared with group I the levels of IL-10 in other groups in BALF were higher (P<0.05). Especially in comparison with group I,M, The levels of IL-10 in group H were higher obviously (P<0.05).6. TNF-α、IL-6 in blood of the fourth hour:Compared with group N, the levels of TNF-a, IL-6 in other groups in BALF were higher constantly (P<0.05). The levels of TNF-a, IL-6 were lower obviously than other groups, especially in comparison with group I, M (P<0.05), and the group H is the most obvious group (P<0.05).7. TNF-α、IL-6 in blood of the twenty-fourth hour:Compared with group N, the levels of TNF-a, IL-6 in other groups in BALF were higher constantly (P<0.05). The levels of TNF-a, IL-6 were lower obviously than other groups, especially in comparison with group I, M (P<0.05), and the group H is the most obvious group (P<0.05).8. IL-10 in blood of the fourth and twenty-fourth hour:Compared with group I the levels of IL-10 in other groups in BALF were higher (P<0.05). Especially in comparison with group I, M, The levels of IL-10 in group H were higher obviously (P<0.05). Compared with group L,the levels in groups M were higher somewhat, but it had no statistic differences (P>0.05)9. The MMP-9 in the lungs of rabbits:group I set high expression, and with the different doses of UTI, the expression level of MMP-9 protein was gradually reduced.10. The MMP-9 mRNA in the lungs of rabbits:Variance analysis showed the MMP-9 mRNA expression level in different groups had statistically difference. Compared with the N group, group I set high expression (P< 0.01). The levels in group H, M, L decreased more significantly in comparison with group I (P< 0.01).11. The NF-κB in the lungs of rabbits:group I set high expression, and with the different doses of UTI, the expression level of NF-κB protein was gradually reduced.12. The NF-κB mRNA in the lungs of rabbits:Variance analysis showed the NF-κB mRNA expression level in different groups had statistically difference. Compared with the N group, group I set high expression (P< 0.01). The levels in group H, M, L decreased more significantly in comparison with group I (P< 0.01).13. Lung tissue under the naked eyes:lung surface in group N appeared with pale pink and even, coated elastically and smoothly, there were not damaged lesions on the surface of lung. It showed that there wasn’t liquid overflow from homogeneous slices. Lung in the group I is dark red, visible extensive hemorrhage stove can be watched anywhere. Lung volume increased significantly, slices were with pink foamy fluid. Group L was similar to group I, lung of group M, H was dark red, subcapsular hyperaemia and edema were relatively lighter.14. Lung tissue pathological slices:the structure of lung tissue in group I was damaged, alveolar sizes were not uniform, and alveolar interval thickened, compensatory emphysema and atelectasis were visible, and alveolar cavity hemorrhaged, there were a large amout of inflammatory cells infiltration, pulmonary interstitial were full of edema of fluid, with occasional transparent membrane formation. The lung tissue damage of structure and function in group L was apparent. The damage in group M, H is lighter than that in group Ⅰ, with group H the most obvious group, and pulmonary edema absorbed obviously; group N was the normal group, the lung structure was essentially normal.Conclusion1. In this topic, the experiment successfully build the animal model of acute lung injury after the rabbits are exposed to the air burst environments.2. High dose of Ulinastatin can obviously reduce the inflammation in the lungs of rabbits with ALI induced by blast. It can also reduce the exudation of protein and relieve edema in the lung. But the effect of low and middle dose of aprotinin is not very well. The mechanism of Ulinastatin which can reduce acute lung injury may be connected with reducing the expression of NF-κB and MMP-9, inhibiting excessive inflammation, reducing the release of TNF-a, IL-6, rising the producing of IL-10. 3. UTI could be a potential drug of ALI. |
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