探讨接种时间和剂量对小鼠肺炎支原体肺炎模型建立的影响

Establishment of a Mouse Pneumonia Model for Mycoplasma pneumoniae Infection in Different Time and Doses

目的用不同时间和剂量建立BALB/c小鼠的肺炎支原体肺部感染模型,探索小鼠急性肺炎支原体感染的过程。方法BALB/c小鼠随机分为Ⅰ、Ⅱ两组,Ⅰ组在0、1、2d滴鼻接种肺炎支原体菌液3次,Ⅱ组在0d滴鼻接种小剂量肺炎支原体菌液1次后于8、9d再接种和Ⅰ组相同的肺炎支原体菌液2次,均设立不同剂量、批次的生理盐水对照组。全部实验动物在3～18d内分批处死。所有小鼠均取肺组织做病理切片。以组织病理学评分来确定小鼠的肺部炎症反应程度。取肺组织匀浆及肺泡灌洗液(BALF)进行肺炎支原体培养做病原学检测。结果接种后实验动物全部存活无死亡。实验组动物均出现不同程度的肺炎支原体肺炎样病理改变,组织病理学评分为1.5～14.3分,分别于第5、6天和第11天达到最高,平均分为4.9分;Ⅰ组实验组动物多呈轻、中度改变,Ⅱ组实验组动物多呈中、重度改变。所有实验组动物肺组织匀浆及BALF的肺炎支原体培养在接种后1月内先后出现阳性结果。对照组动物未出现明显肺部炎症改变,组织病理学评分为0～1分,肺炎支原体培养为阴性。结论成功建立BALB/c小鼠的肺部肺炎支原体感染模型;组织病理学评分方法可用以评价肺部炎症反应的严重程度;不同接种时间和剂量所致的病变程度不同。

Objective To establish a mouse pneumonia model for Mycoplasma pneumoniae （MP） infection at different times and doses, and examine the progression of the pneumonia in mice. Methods BALB/c mice were randomly grouped. Group I was inoculated intranasally with MP suspension on days 0, 1, and 2. Group Ⅱ was inoculated on days 0, 8, and 9. Control groups were set up with sterile normal saline. Mice were sacrificed on 3 - lg days. MP was detected by culturing the lung tissues and brochoalveolar lavage fluid （BALF） of each mouse. Lung tissue sections were examined and a his- topathological scoring system was applied to judge the severity of the inflammation. Results All of the mice survived after inoculation. The infected animals showed inflammatory changes in the lungs varying grades. The MP cultures of lung and BALF specimens from infected animals were positive and negative from the control groups. Histopathologic scores ranged from 1.5 to 14.3. Conclusion The mouse pneumonia model for MP infection was established successfully and the his- topathological scoring system can be used to evaluate the severity of acute inflammatory lesions of the lung on BALB/c mice. The model provided an experimental basis for further study of the pathogenesis and immunological state after MP infection.