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Background: Acute lung injury (acute lung injury, ALI) is a common clinical critical illness, by a variety of extrapulmonary disease risk factors lead to increased vascular permeability as a major clinical manifestations of lung inflammation syndrome, the incidence The mechanism is very complex and high mortality. Its pathology showed infiltration of inflammatory cells in the alveolar spaces, alveolar capillary endothelial injury, increased permeability, pulmonary edema, and ultimately lead to the destruction of the integrity of the alveolar wall. There is close association between early lung injury tissue reconstruction and advanced pulmonary fibrosis. More etiology, pathogenesis is not very clear, there is no effective treatment method. Endotoxin is one of the important factors that lead to ALI. Explore LPS caused ALI onset of molecular mechanisms and new intervention targets to reduce or prevent the occurrence and development of ALI, has important clinical significance. The study shows that the transforming growth factor-β (Transforming growth factor P, TGF-β) play a critical role in multiple organs, including the lungs, including the tissue damage. Activation of TGF-β type III receptor regulatory role, first in combination with two type II receptor raised two type I receptor to form a complex, the GS functional domains Ⅰ receptor phosphorylation, it activation, along with the type I receptor activation re-phosphorylation of downstream signaling molecules Smads protein biological effect. But exactly which several TGF-β Ⅰ receptor subtype involved in the occurrence and development process of the ALI is unclear. Therefore, we study the TGF-β Ⅰ receptor subtypes ALK-1, 2,3,5 distribution and variation in the occurrence and development of normal lung tissue and ALI, filter out the high expression in ALI receptor subtypes, in order to reached to reduce or prevent ALI role. Objective: To identify the TGF-β Ⅰ receptor subtype of ALK-1, 2,3,5 in normal lung tissue and LPS-induced ALI distribution and variation; explore the TGF-β type I receptor subtypes in ALI expression, a comprehensive analysis of the TGF-β Ⅰ receptor subtype distribution and variation in the occurrence and development of ALI for the prevention and treatment of ALI provides a new theoretical basis. Methods: acute lung injury in animal models, by real-time quantitative PCR (Real Time-PCR) technology to detect the distribution and variation of the TGF-β Ⅰ receptor subtypes in the occurrence and development of normal lung tissue and ALI combined pathological changes of the lung tissue, filter out meaningful TGF-β Ⅰ receptor subtypes. RESULTS: HE staining of pathological observation HE staining the parties modules have varying degrees of alveolitis, alveolar space varying degrees of inflammatory cell infiltration. 8h group of inflammatory cell infiltration, 24h and 48h in addition to inflammatory cell infiltration, alveolar space also visible pale red liquid oozing. The the 72h group see the phenomenon of pulmonary edema is reduced, compared with the previous but still inflammatory cell infiltration. 7 days group to see the decrease in the number of inflammatory cells, edema fluid is gradually absorbed. 2.Real Time-PCR results show that: Compared with the normal group, model group, ALI rat alveolar lavage TGF-β Ⅰ receptor ALK-1 mRNA expression in damage after 48h began to rise and extend the time with the inflammation gradually increased and reached the peak at 72h, after a decline in; ALK-3 mRNA with lung injury time was gradually rising trend, peaked at 24h, after gradually decline again increased to 72h, and then decreased gradually. TGF-β Ⅰ receptor subtypes ALK-5 mRNA expression after LPS injection 8h increased, along with a decline in injury time, the lowest level at 24h, and then gradually increased and reached a peak within 7 days. ALK-2 mRNA expression after injury is always in the low state, did not significantly higher. Analysis of variance, using repeated measurement data of TGF-beta type I receptor subtypes time point, all P <0.05, significant. Conclusion: ALK-1, ALK-3, ALK-5 in the development process of ALI showed high expression may be involved in the development of ALI occurrence.
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