冲击波强度与幼年大鼠肺冲击伤程度的量效关系

目的:探索冲击波强度与幼年大鼠肺冲击伤程度的量效关系，为儿童冲击伤研究提供动物模型和基础。方法:选取20天龄幼年健康SD雄鼠40只，随机分为4组:BIG1、BIG2、BIG3和BIG4，每组各10只，采用BST-Ⅰ型生物激波管以4.8~5.8 MPa驱动压致伤，观察各组动物伤后生命体征、肺大体解剖和光镜病理等，并进行肺冲击伤严重程度评分。结果:幼鼠在驱动压致伤后均出现了不同程度的呼吸急促、心率加快的表现，外耳道出血发生率为57.5%（46/80）。肺大体解剖表现为不同程度的肺出血、水肿和肺不张等。光镜下病理主要表现为不同程度的肺出血、渗出、炎症细胞的浸润、肺间质水肿增厚、肺泡内水肿和肺泡壁的断裂等。4.8 MPa驱动压时，动物所受超压峰值为433 kPa，正向冲量14 226.4 kPa?m，肺器官损伤定级（OIS）集中在Ⅱ、Ⅲ级（40%、30%），肺冲击伤简明损伤定级（AIS）评分为0.90±0.57，损伤程度为轻度；5.0 MPa驱动压时，超压峰值为447.7 kPa，正向冲量14 463.5 kPa?m，OIS多集中在Ⅲ级（60%），AIS评分为1.60±0.69，损伤程度为中度；5.5 MPa驱动压时，超压峰值为484.7 kPa，正向冲量15 017.0 kPa?m，OIS多集中在Ⅳ级（70%），AIS评分为3.10±0.56，损伤程度为较重；5.8 MPa驱动压时，超压峰值为506.8 kPa, 正向冲量15 325.5 kPa?m，OIS集中在Ⅴ级（40%）附近，AIS评分为4.00±0.67，肺损伤程度为重度。各组间损伤严重程度有明显统计学差异（P<0.05）。结论:利用BST-I型生物激波管，采用4.8~5.8 MPa高压段的驱动压可建立稳定的幼年SD鼠轻~重度肺冲击伤模型。幼年大鼠肺组织对冲击波损伤的耐受性强于成年大鼠肺组织，也强于幼年兔肺组织，其机制尚不太清楚，值得进一步深入研究。

Dose-effect relationship between shock wave intensity and blast lung injury in juvenile rats

Abstract: Objective To explore the dose-effect relationship between shock wave intensity and blast lung injury in juvenile rats, thereby providing animal model and research foundation for the study on blast injury in children. Methods A total of 40 healthy SD male rats of 20 days old were randomly divided into 4 groups, namely BIG1, BIG2, BIG3 and BIG4, with 10 in each group. The rats were injured by BST-I bioshock tube with actuating pressures at 4.8 MPa to 5.8 MPa. The vital signs after injury as well as the gross anatomy and light microscope pathology of the lungs in each group were analyzed, and then the severity of blast lung injury was scored. Results All the juvenile rats showed different degrees of shortness of breath and heart rate increasing after injury, and the incidence of external auditory canal hemorrhage was 57.5% (46/80). The gross anatomy of the lungs was characterized by various degrees of lung hemorrhage, edema, atelectasis and so on. The pathological changes observed by light microscopy mainly included different degrees of lung hemorrhage, effusion, inflammatory cells infiltration, thickening and edema of pulmonary mesenchyme, alveolar edema, alveolar wall rupture and so on. At an actuating pressure of 4.8 MPa, the peak value of overpressure on the animal was 433 kPa the positive impulse was 14 226.4 kPa?m organ injury scaling (OIS) was concentrated in grade II and III (40%, 30%) abbreviated injury scale (AIS) score was 0.90±0.57 and it was finally diagnosed as mild lung injury. When the actuating pressure was 5.0 MPa, peak overpressure and positive impulse were 447.7 kPa and 14 463.5 kPa?m, respectively and the lung injury was concentrated in OIS grade III (60%), with an AIS score of 1.60±0.69 and it was finally diagnosed as moderate lung injury. When the actuating pressure was 5.5 MPa, peak overpressure and positive impulse were 484.7 kPa and 15 017.0 kPa?m, respectively and the lung injury was concentrated in OIS grade IV (70%), with an AIS score of 3.10±0.56 and it was finally diagnosed as relatively severe lung injury. When actuating pressure was 5.8 MPa, peak overpressure and positive impulse were 506.8 kPa and 15 325.5 kPa?m, respectively the lung injury was concentrated near OIS grade V (40%), with an AIS score of 4.00±0.67 and it was finally diagnosed as severe lung injury. Statistically significant difference was found in the severity of lung injury among different groups (P<0.05). Conclusion A stable model of mild-to-severe blast lung injury in juvenile SD rats can be established using BST-I bioshock tube with actuating pressures at 4.8 MPa to 5.8 MPa. The lung tissues of juvenile rats are more tolerant to blast injury than lung tissues of adult rats and juvenile rabbits, while the mechanism is still unclear and deserves further research.