Comparative Proteomic Study Of Acute Pulmonary Embolism In A Rat Model

Pulmonary embolism(PE) is a common, potentially fatal disease, whose blood clots originate from the deep venous system of the lower extremities. Pulmonary embolism is of clinical importance because of the considerable mortality and morbidity. In this study, we successfully constructed a rat model of pulmonary embolism, and then comparative proteomic analysis is utilized to achieve the protein profiles of pulmonary tissue proteins and sera proteins in order to find differentially expressed proteins. Information from this study may be helpful to uncover the pathophysiologic molecular mechanisms involved in pulmonary embolism, and those differentially expressed proteins may be candidates of bio-marker.At first, we constructed a rat pulmonary embolism model by injecting 3-4 emboli into the left jugular vein. Before collecting the lung tissue, we perfused it with saline through the right jugular to remove the blood. The acetone-TCAprecipitation is adopted to prepare the protein sample in order to remove those contaminants such as salts, small ionic molecules, ionic detergents, nucleic acids, polysaccharides, lipids, and phenolic compounds. In this study we separated and identified differentially expressed proteins in lung tissue and sera at different time spots using the techniques of two-dimensional electrophoresis (2-DE) and mass spectrometer (MS). After image analysis of lung tissue proteins, we obtained about 1 800 spots by Coomassie staining and above 2 000 spots by silver staining. Forty-six protein spots of interest were excised from the gels and identified by matrix assisted laser desorbtion/ionization time-of-flight mass spectrometer(MALDI-TOF-MS). Thirty-two protein spots found their corresponding protein candidates in the database. They could be divided into nine kinds: the first was associated with the contractive function of smooth muscules in vascular system and tracheae; the second was about the metabolism of collagen in lung tissue; the third was associated with the apoptosis and injury of lung tissue cells; the fourth was about the metabolism of toxicant; the fifth was about the blood pressure adjustment; the sixth was about the erythrocyte differentiation; the seventh was about the aerobic metabolism; the eighth was about maintaining the acid-base balance of the body; the ninth were new proteins, which weren't be studied before. Seven of the identified proteins were validated by semi-quantitative RT-PCR, and three of them were validated by western blot analysis. The differential expression patterns of these proteins suggest the distinct roles they may play in different stages of the rat pulmonary embolism model.In the study of sera proteins, HiTrap? Blue HP from Amersham Pharmacia was used to remove the high abundant albumin but was abandoned at last since the protein spots from treated sera were fewer than untreated sera. After image analysis of sera proteins, we obtained about 1 200 spots by Coomassie staining...