肺炎克雷伯杆菌致大鼠重症肺炎模型的改良与评估

 目的：采用肺炎克雷伯杆菌标准菌株感染SD大鼠，建立大鼠重症肺炎模型, 探讨重症肺炎动物模型诊断标准。方法：取25只大鼠随机分成对照组、观察组和模型组，其中对照组和观察组各5只，模型组15只。通过气管内注射的方式，模型组和观察组分别接种相同剂量不同浓度的肺炎克雷伯杆菌菌液，对照组接种生理盐水。动态观察大鼠行为学、体温、体重、肢端血氧饱和度 (SaO2)、外周血象和动脉血气变化，观察肺组织病理改变和胸部X线检查变化等。对照组和观察组在术后72 h处死存活大鼠，模型组在达到预定的诊断标准后处死。结果：大鼠用无创血氧饱和度仪检测得到的数值与有创动脉血气分析中SaO2的数值基本一致；与观察组比较，模型组行为学变化、体重变化、肺组织病理改变和胸部X线检查明显加重，外周血象、SaO2和动脉血气变化存在明显差异（P<0.05）；对照组各项观察指标在手术前后无明显变化。结论：注射高浓度菌液可以建立重症肺炎动物模型，预定的诊断标准对判断动物重症肺炎模型成功与否有一定的指导作用；无创动脉血氧饱和度仪可以用于监测大鼠SaO2变化。

Evaluation of an improved rat model of Klebsiella pneumoniae-induced severe pneumonia

AIM：To establish and evaluate the diagnostic criteria of severe pneumonia in a rat model. METHODS：Twenty-five SD rats were randomly divided into control group (n=5), observation group (n=5) and model group (n=15). The rats in model group and observation group were intratracheally inoculated with different concentrations of Klebsiella pneumoniae bacteria suspension, and the rats in control group were inoculated with saline. Dynamic observations of behavior, body temperature, body weight, oxygen saturation (SaO2), peripheral blood changes and arterial blood gas were conducted. The pathological changes of the lung tissue were observed, and the chest X-ray examination was performed. The rats in control group and observation group were sacrificed 72 h after operation, and the rats in model group were sacrificed if they met the diagnostic criteria. RESULTS：SaO2 detected by the noninvasive oximeter was almost the same as that detected by invasive arterial blood gas analysis. Compared with observation group, the behavior, body weight, the changes of lung pathology and chest X-ray in model group changed obviously. The peripheral blood, SaO2, and arterial blood gas also changed significantly. No significant difference of the indexes above was observed in control group before and after operation. CONCLUSION：Injection of high concentration of bacteria successfully induces severe pneumonia in the rats. The diagnostic criteria can be used for evaluating the animal model with severe pneumonia. With a noninvasive oximeter, we can generally monitor the changes of SaO2 in the rats.