ABSTRACT
Objective@#To observe the dynamic impacts of shock waves on the severity of lung injury in rats with different injury distances.@*Methods@#Simulate open-field shock waves; detect the biomechanical effects of explosion sources at distances of 40, 44, and 48 cm from rats; and examine the changes in the gross anatomy of the lungs, lung wet/dry weight ratio, hemoglobin concentration, blood gas analysis, and pathology.@*Results@#Biomechanical parameters such as the overpressure peak and impulse were gradually attenuated with an increase in the injury distance. The lung tissue hemorrhage, edema, oxygenation index, and pathology changed more significantly for the 40 cm group than for the 44 and 48 cm groups. The overpressure peak and impulse were significantly higher for the 40 cm group than for the 44 and 48 cm groups ( < 0.05 or < 0.01). The animal mortality was significantly higher for the 40 cm group than for the other two groups (41.2% . 17.8% and 10.0%, < 0.05). The healing time of injured lung tissues for the 40 cm group was longer than those for the 44 and 48 cm groups.@*Conclusions@#The effects of simulated open-field shock waves on the severity of lung injuries in rats were correlated with the injury distances, the peak overpressure, and the overpressure impulse.
Subject(s)
Animals , Male , Rats , Biomechanical Phenomena , Blast Injuries , Pathology , Disease Models, Animal , Explosions , Lung Injury , Pathology , Random Allocation , Rats, Sprague-DawleyABSTRACT
Objective: To prepare the vascular endothelial growth factor(VEGF)and basic fibroblast growth factor(bFGF)-loaded poloxamer thermosensitive gels and investigate the in vitro drug release property as well as the therapeutic effect of the drug-loaded thermosensitive gels on the full-thickness skin defected wound healing in rats. Meth- ods: The release of VEGF and bFGF from the drug-loaded gels in vitro was determined by the membrane release meth- od. The full-thickness skin defected model of rats was established and divided into four groups: the normal saline(Con- trol)group, poloxamer thermosensitive gel(Gel)group, freeze-dried VEGF and bFGF powder(VEGF/bFGF powder) group, and the VEGF/bFGF-loaded poloxamer thermosensitive gel(VEGF/bFGF-loaded gel)group. The wound healing was observed on the 3rd, 7th and 14th day of injury. The wound tissue was stained with hematoxylin-eosin. The wound healing and inflammation were observed under the microscope. The expression of CD31 was measured by the immunohis- tochemical staining and the number of new blood vessels was counted. The content of inflammatory factors in the wound was detected by ELISA. Results: The VEGF/bFGF-loaded poloxamer thermosensitive gels were successfully prepared. The in vitro drug release test showed that only about 5% of VEGF and bFGF in the drug-loaded gels was released from the gels within 1 h of the test, however, the subsequent VEGF and bFGF release could reach 60% on the fifth day of the re- lease test, suggesting the well sustained drug-release behavior of the VEGF/bFGF-loaded gels. In the wound healing test using the full-thickness skin defected rat model, the wound healing rate reached(90.3±2.4)% on the 14th day of injury, in the VEGF/bFGF-loaded gel group, which was significantly higher than that in the other groups(P<0.05). On the 3rd day of injury, compared with the Control and Gel groups, the level of IL-6 and TNF-α in the wound was significantly de- creased in the VEGF/bFGF-loaded gel group(P<0.05). The tissue HE staining showed that the skin wound healed well in the VEGF/bFGF-loaded gel and the VEGF/bFGF powder groups, and a lager number of neovascularization and the epi- dermis appeared earlier in both the VEGF/bFGF-loaded gel and the VEGF/bFGF powder groups than in the Control and the Gel groups. The immunohistochemical results further confirmed that the number of neovascularization was significant- ly higher in the VEGF/bFGF-loaded gel and the VEGF/bFGF powder groups than in the Control and Gel groups(P< 0.05). Conclusion: The prepared VEGF/bFGF-loaded poloxamer thermosensitive gels in the present study could be used to repair the full-thickness skin defected wound in rats, which could reduce the early inflammatory reaction, pro- mote the angiogenesis, and thus accelerate the healing.