不同浓度肺炎链球菌造成大鼠脑膜炎模型的实验研究

Study of bacterial meningitis models in rats induced by different concentration of bacteria

目的通过不同浓度肺炎链球菌造成大鼠细菌性脑膜炎模型,选出最合适的造模菌株。方法 3周龄SD大鼠40只随机分为生理盐水对照组(10只)、细菌性脑膜炎模型组(模型组分3组,每亚组各10只)。应用不同浓度(106、107、108cfu/mL)肺炎链球菌Ⅲ型对大鼠脑池穿刺建立细菌性脑膜炎模型,应用等体积生理盐水替代肺炎链球菌作对照组,观察终点为动物自然死亡或造模5d。比较各组大鼠病死率、生理指标变化、Loeffler神经行为学评分、脑组织形态学改变表达。结果高浓度组较低浓度组病死率高,体质量增长慢,体温升高快;Loeffler神经行为学评分低,脑组织水肿明显(P均<0.05)。结论脑池内直接注射细菌后,能诱导出细菌性脑膜炎。通过控制菌株浓度,可造成不同程度的脑膜炎模型。107cfu/mL为最佳造模浓度。

Objective To choose the most approprite bacterial concentration to induce bacterial meningitis model.Methods Sprague-Dawley rats on postnatal 3weeks were divided into 4groups randomly.The model groups were established by direct intracisternal injecting different concentration of streptococcus pneumoniaeⅢ（SPⅢ）（106,107,108 cfu/mL）into cerebellomedullary cistern,the saline（NS）control group was injected by NS.The end was the death of the rats or days after model established.The rats were observed death rate,the physiological index,Loeffler＇s neuroethology score,etc.Results The death rate of high concentration group was higher than that of the low concentration group,while the weight growth was slower,the body temperature increased faster,Loeffler neurobehavioral score was lower and brain tissue was more obviously edema（P0.05）.Conclusion Bacterial meningitis model could be induced by direct intracisternal injection of a suspension of SPⅢ on postnatal 3weeks in SD rats.To control the concentration of the bacteria could control the degree of the bacterial meningitis model.107cfu/mL was the most comfortable concertration to induce the model.