Study On The Angiopoietin-2 And Its Mechanism In Acute Lung Injury

Part I The preparation of the acute lung injury model of rat and the selection of sampling timeObjective: To explore the selection of sampling time during the process for preparing the acute lung injury model of rat,which is to provide a scientific basis for the successful establishment of the acute lung injury model of rat.Methods : 30 adult male SD rats were randomly divided into 6 rats of normal saline control group(control group)and 24 rats of LPS group. LPS group rats were injected 1 ml LPS of 10mg/kg concentration via caudal vein for acute lung injury modeling, while control group rats were injected l ml saline solution via caudal vein. Take 6 rats separately from control group and LPS group after 1, 3, 6, 12 h of injection, for lung tissue detection of wet to dry ratio, lung tissue pathology morphology observation by the light microscope, expression detection of vascular endothelial growth factor by using immunohistochemi-stry, and expression detection of serum interleukin-6 and vascular endothelial growth factor by using ELISA method. Results : after 1h of LPS injection, LPS group were obviously lung interstitial edema and inflammatory cell infiltration; after 1, 3, 6, 12 h, lung tissue wet to dry ratio(5.57±0.55、5.81±0.81、6.11±0.68、5.84±0.52), lung injury rating((1.17±0.41)、(2.33±0.52)、(3.50±0.55)、(2.83±0.75)points), serum interleukin-6((31.33±6.95)、(78.33±7.53)、(95.17±10.93)、(72.00±10.30)pg/ml)and vascular endothelial growth factor((228.17±17.30)、(284.33±18.74)、(384.50±29.22)、(316.33±26.80)pg/ml)of LPS group were significantly higher than which of control group((5.19±0.98)、(0.00±0.00)point、(9.00±3.85)pg/ml、(197.50±15.18)pg/ml)(P<0.05). Among which, the data after 6h was significantly higher than after1, 3, 12 h; and the data after 3, 12 h was higher than after 1 h(P < 0.05).Conclusion: the modeling for rat of acute lung injury would be successful after6h of tail vein injection with 10 mg/kg LPS.Part II The function of Angiopoietin-2 in acute lung injuryObjective: To investigate the angiopoietin-2(Ang-2) in acute lung injury(AL I) the occurrence and development role. Methods: 48 SD rats were randomly divided into four groups: normal control group(12), 1mg / kg LPS group(12), 5mg / kg LPS group(12), 10 mg / kg LPS group(12). HE staining light microscope pathological changes in lung tissue and lung injury score, expression and plasma Westernblot by ELISA technique to detect the rat Ang-2’s. Results: LPS injected into the tail vein of rats 6 h, light microscope, pulmonary interstitial edema and inflammatory cell infiltration, lung wet / dry weight ratio(W / D) increased expression levels of serum Ang-2 than in the control group was significantly higher(P <0.05), and the expression levels of different doses of LPS and Ang-2 in a dose-dependent manner. Conclusion: Ang-2 involved in the pathological process of acute lung injury, and serum levels of Ang-2 showed a degree of positive correlation with acute lung injury.Part III The research of Ang-2 in rats with acute lung injury and lung tissue LPS-induced apoptosistissue and Ang-2 expression in acute lung injury in rats, to explore LPS-induced acute lung injury(ALI) in the pathogenesis. Methods: 48 healthy male SD rats were randomly divided into two groups: ① control group: intravenous saline; ②LPS groups: intravenous injection of LPS Rat models ALI, were given 1mg / kg LPS(12 只), 5mg / kg LPS(12 只), 10 mg / kg LPS(12 rats) after the samples were collected, using bcl-2, bax levels were detected by immunohistochemistry in lung tissue, the expression of Caspase-3; Ang2 and apoptosis were observed in rat relationship. Light microscopy of lung tissue pathological changes Results: Compared with the control group. Ang-2 expression in LPS group, dose-dependent enhancement, immunohistochemistry showed, LPS group, Bcl-2 increased with dose reduction, mainly in lung epithelial cells, increased Bax, increased caspase-3 protein levels; the control group had no significant change. Conclusion: Different doses of LPS-induced expression of Ang-2 in different degrees of acute lung injury, the anti-apoptotic protein Bcl-2 and pro-apoptotic protein Bax is one way to regulate apoptosis when ALl; Ang-2 may By adjusting the balance of Bcl-2 and Bax affect lung tissue apoptosis. Objective: To observe the relationship between endotoxin-induced apoptosis in lung...