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Objective: To establish an adult rat model of lung blast injury in laboratory for providing a reliable rat model for the diagnosis and treatment of lung blast injury. Methods: According to the different injury driving pressure of BST-I biological shock tube, 40 adult SD male rats aged 7 to 8 weeks were randomly divided into 4 groups (10 each): 4.5 MPa group, 4.8 MPa group, 5.0 MPa group and 5.5 MPa group. The general physiological and 24-hour survival status of rats in each group were recorded before and after modeling. The survived rats 24 h after modeling were anesthetized and then killed, and the chest anatomy was performed. The characteristics of lung injury were observed, the degree of lung tissue injury was graded using organ injury scaling (OIS) and abbreviated injury scale (AIS). Furthermore, the left lower part of lung tissue was taken for routine pathological section, and the degree of lung tissue injury was observed under light microscope. Results: All rats were successfully modeled and survived 24 h after injury, and showed shortness of breath and accelerated heart rate without hematuria and blood stool. There were significant differences among the four groups in bleeding rate of external auditory canal, anal temperature and pulmonary bleeding area (P5.0 MPa>4.8 MPa>4.5MPa. Under light microscope, rats in the four groups showed varying degrees of pulmonary hemorrhage, edema and atelectasis, and the lung tissue was ruptured. Conclusion: The stable adult SD rat models of mild, moderate, severe and extremely severe lung blast injury have been established.
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<p><b>Background</b>The increasing frequency of explosive injuries has increased interest in blast-induced traumatic brain injury (bTBI). Various shock tube models have been used to study bTBI. Mild-to-moderate explosions are often overlooked because of the slow onset or mildness of the symptoms. However, heavy gas cylinders and large volume chambers in the model may increase the complexity and danger. This study sought to design a modified model to explore the effect of moderate explosion on brain injury in mice.</p><p><b>Methods</b>Pathology scoring system (PSS) was used to distinguish the graded intensity by the modified model. A total of 160 mice were randomly divided into control, sham, and bTBI groups with different time points. The clinical features, imaging features, neurobehavior, and neuropathology were detected after moderate explosion. One-way analysis of variance followed by Fisher's least significant difference posttest or Dunnett's t 3-test was performed for data analyses.</p><p><b>Results</b>PSS of mild, moderate, and severe explosion was 13.4 ± 2.2, 32.6 ± 2.7 (t = 13.92, P < 0.001; vs. mild group), and 56.6 ± 2.8 (t = 31.37, P < 0.001; vs. mild group), respectively. After moderate explosion, mice showed varied symptoms of malaise, anorexia, incontinence, apnea, or seizure. After bTBI, brain edema reached the highest peak at day 3 (82.5% ± 2.1% vs. 73.8% ± 0.6%, t = 7.76, P < 0.001), while the most serious neurological outcomes occurred at day 1 (Y-maze: 8.25 ± 2.36 vs. 20.00 ± 4.55, t = -4.59, P = 0.048; 29.58% ± 2.84% vs. 49.09% ± 11.63%, t = -3.08, P = 0.008; neurologic severity score: 2.50 ± 0.58 vs. 0.00 ± 0.00, t = 8.65, P = 0.016). We also found that apoptotic neurons (52.76% ± 1.99% vs. 1.30% ± 0.11%, t = 57.20, P < 0.001) and gliosis (2.98 ± 0.24 vs. 1.00 ± 0.00, t = 14.42, P = 0.021) in the frontal were significantly higher at day 3 post-bTBI than sham bTBI.</p><p><b>Conclusions</b>We provide a reliable, reproducible bTBI model in mice that can produce a graded explosive waveform similar to the free-field shock wave in a controlled laboratory environment. Moderate explosion can trigger mild-to-moderate blast damage of the brain.</p>
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Objective To establish an animal model of severe blast lung injury in baby rabbits,and to provide a way to study the char-acteristic and treatment of blast lung injury in minors.Methods Randomly selected sixteen 4-weeks old New Zealand white rabbits,and the blast lung injuries were made by BST-Ⅰ biological shock tube with different drive pressure (4.0 MPa and 4.5 MPa)respectively.Then compared the injury severity of the 4.0 Mpa group and the 4.5 MPa group.Selected forty-eight 4-weeks old New Zealand white rabbits and di-vided them into the control group (8 rabbits)and the blast lung injury group (40 rabbits)Rabbits in the blast lung injury group were injured with 4.5 MPa drive pressure.Observed the vital signs,physiological index,gross anatomy of the lung,pathology,and pulmonary water content at the time of injury immediately (0 hour),2 hours,4 hours,6 hours,12 hours,24 hours,48 hours and 72 hours after the injury.Results Rabbits inthe 4.0 Mpa group and the 4.5 MPa group were all alive.The overpressure of blast wave of the 4.0Mpa group was (328.16 ± 4.78)kPa,rate of severe pulmonary defense was 12.5%,and the AIS score was (3.38 ±0.52)points.In the 4.5 MPa group,the overpressure of blast wave was (395.04 ±11.74)kPa,rate of severe pulmonary defense was 87.5%,and the AIS score was (4.13 ±0.64) points.Rabbits in the control group and the blast lung injury group were all alive.The spirits of rabbits were drooping immediately after inju-ry,and it last about 0.5 hour.Then the breathing and heart rate was accelerated,pulmonary water content was increased significantly,and there were extensive hemorrhage and edema in the lung.Most of the rabbits suffered severe lung injury,and the AIS score was (3.98 ±0.55) points.Lung tissue rupture,hemorrhage,edema,and inflammatory cells infiltration were the main pathological manifestations under light microscopy. Conclusion The model of severe blast lung injury in baby rabbits could be established with BST-Ⅰbiological shock tube and drive pressure of 4.5 MPa.It is relatively simple,easily controllable and highly repeatable,which can be used as a feasible model for the study of blast lung injury.
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Thirty-four dogs were inflicted with blast injury from a shock tube with a diameter of 348 mm. The peak value of the overpressure was 1.05~1.33kg/ cm2, the effective time of the overpressure 40~45 milliseconds, and the speed of the blast wave 473~509m/s. There were 11 dogs (32.4%) with very severe damage, 5 (14.7%) with severe damage, 17 (50%) with moderate damage and 1 with mild damage. The peak value and the effective time of the overpressure were the decisive factors to determine the severity'of the damage, and the posture of the animal at the time of blast impact might also be important. The sensivity of different organs to the blast wave was not uniform, it was related to the position, size, degree of dissociation, and structural characteristics of the organ concerned. The order of the sensitivity of various organs, from highly to less sensitive, could be arranged as follows; the audotory apparatus, the liver, the lungs, the spleen, the heart, the urinary bladder, and the kidneys. It is suggested that in diagnosing a case of blast injury, an examination of the audotory apparatus and a total and differential white count be of value.The pathological changes caused by the blast wave from a shock tube were similar to those caused by nuclear explosion in nature but milder in degree since the effective time of the overpressure of the shock tube wave was shorter. The chief causes of early death of the animals with blast injury were massive hemorrhage and cranial injury.