ABSTRACT
[Abstract] Objective To explore the regular pattern of the changes of vascular endothelial growth factor (VEGF) and neuropilin-1 (NRP-1) of rat model in early (<48h) blast lung injury (BLI) and the correlation of such changes to the degree of lung injury. Methods The rat model of lung blast injury was established with reducing three-way pipe and fixed pressure pneumatic simulation device. Forty SD rats were randomly divided into 5 groups: control group (C), 1h after blast (B1h), 6h after blast (B6h), 24h after blast (B24h) and 48h after blast (B48h) group. The data were collected of concentrations of VEGF and NRP-1 in serum and lung tissue. The degree of lung injury was estimated. Results The levels of NRP-1 increased in both serum and lung tissue (P<0.01) and the level of VEGF decreased in lung tissue (P<0.05) in control group than in B groups. The concentrations of NRP-1 in serum and lung tissue were highest, and of VEGF in lung tissue were lowest in the group B6h. The lung injury score was positively correlated with the levels of NRP-1 in lung tissue (r=0.429, P=0.014). In group B6h, the lung injury score was negatively correlated with the levels of VEGF in lung tissue (r=–0.769, P=0.013). In group B48h, both the lung injury score and the wet and dry ratios (W/D) of lung tissue were positively correlated with the concentrations of VEGF in serum (r=0.777, P=0.012 and r=0.687, P=0.030, respectively). Pulmonary interstitial vascular rupture, alveolar hemorrhage, alveolar epithelial cell and capillary injuries, and accompanied by inflammatory cell infiltration were the basic pathological changes of BLI. Conclusion The levels of NRP-1 and VEGF in serum and lung tissue may vary with time and are correlated with the degree of lung injury in early BLI.
ABSTRACT
Objective At present, the model of pulmonary blast injury is characterized by complexity, a certain degree of safety risks,and difficulty in obtaining the materials.This article aimed to establish a simple, safe and reusable primary pulmonary blast injury model in rats. Methods A total of 16 SD rats were randomly divided into control group and pulmonary blast injury group. In rats of control group, only ketamine(120 mg/kg)was injected intraperitoneally and hair was removed from chest.In pulmonary blast injury group,after the rats were fully anesthetized and depilated on chest,they were placed in a reducing T-pipe with only chest fully exposed,and the pneumatic simulated blasting device was adjusted to 0.4 Mpa.Taking locations about 2.5 cm from the intersection points of the median line of the sternum with left and right anterior axillary lines as targets,explosion were carried out respectively,fol-lowing the sequence of right chest 2 min prior to left chest.Lung pathology,lung water content,arterial blood gas analysis, and inter-leukin-6(IL-6)changes were observed. Results No obvious dam-age was found as to the appearance of chest in all rats after blast inju-ry.Transient purpura appeared in 37.5%(3/8)of the rats within 5 min after injury and disappeared within 1 h.On the spot,62.5%(5/8)of the rats presented 10-20 s of brief apnea and gradually recov-ered 6 h later.The lung tissue W/D,serum IL-6 level and lung tissue IL-6 level in pulmonary blast injury group were significantly greater than those in control group[(4.97±0.37)vs(4.62±0.07),(68.13± 59.40)vs(16.27 ±5.08)pg/mL,(487.04 ±30.57)vs(172.74 ±35.02)pg/mL],representing statistically significant difference(P<0.05).PaO2level in pulmonary blast injury group was significantly lower than that of control group,and the difference was statistically significant(P<0.05).After pulmonary blast injury, punctate and flaky hemorrhages were observed in the lesions of lung tissues,showing red hepatic changes.Lung interstitium was obviously thickened and alveoli collapsed under microscope.Erythrocytes and edema fluid in lung interstitium and alveoli exuded.Gas embolism in intersti-tial blood vessels was observed under microscope. Conclusion The lungs of rats after blast through simple T-pipe is typical of prima-ry pulmonary blast injury in pathological and pathophysiological manifestations, which proves the convenience and reliability of the modeling method.