牛种布鲁氏菌2308不同途径小鼠感染模型的建立与评估

Establishment and evaluation of mice model infected Brucella abortus strain 2308 by different routes

摘要:

[背景] 布鲁氏菌可经口、皮肤、黏膜和呼吸道感染人和动物。小鼠是布鲁氏菌研究中最常用的模型动物。[目的] 建立牛种布鲁氏菌2308不同途径和剂量感染BALB/c小鼠的模型，为布鲁氏菌小鼠感染试验提供参考。[方法] 用10¹-10⁵ CFU这5个不同感染剂量，分别经注射、口服和点眼方式感染BALB/c小鼠。在感染后不同时间点采集小鼠血清，检测IgG、IgM、IgA抗体含量、脾脏重量及脾脏含菌量，评价布鲁氏菌经不同途径感染BALB/c小鼠的效果。[结果] 10 CFU是注射感染BALB/c小鼠的最小感染剂量；10⁵ CFU是口服感染BALB/c小鼠的最小感染剂量。10¹-10⁵ CFU这5个不同感染剂量经点眼途径均未能成功感染BALB/c小鼠。在10⁵ CFU感染剂量下，口服与注射感染组小鼠每克脾脏平均含菌量分别为10^5.673 CFU/g和10^5.009 CFU/g，无显著差异（P>0.05），但口服感染组小鼠脾脏平均重量为0.310 g，显著高于注射感染组0.165 g （P<0.01）。在试验期内，注射感染组和口服感染组小鼠体内IgG抗体的滴度均随感染时间延长而持续升高；整体上，口服感染组IgG抗体峰值显著高于注射感染组；2组IgM抗体变化趋势一致；口服感染组有2只小鼠在感染28 d后产生IgA抗体，注射感染组均未检测到IgA抗体。[结论] 建立了牛种布鲁氏菌2308通过不同途径感染BALB/c小鼠的模型。

关键词:牛种布鲁氏菌;小鼠感染模型;每克脾脏含菌量

Abstract:

[Background] Brucella can infect humans and animals by mouth, skin, mucous and respiratory tract. Mice are the most commonly used model animals in the study of Brucella. [Objective] The study aimed to establish the BALB/c mice model infected by Brucella abortus strain 2308 with different routes and doses, and to provide reference for mice infection experiments by Brucella. [Methods] The BALB/c mice were infected with 5 different doses of 10¹-10⁵ CFU by injection, mouth and eye droppings respectively. The serum samples were collected at different time points after infection in order to detect IgG, IgM and IgA antibodies. Combined with the results of spleen weight and bacteria content, we evaluated the effect of BALB/c mice model infected with Brucella by different routes. [Results] The results showed that 10 CFU was the minimum infection dose for injection, and 10⁵ CFU was the minimum infection dose for oral administration. The BALB/c mice could not be successfully infected with 5 different doses of 10¹-10⁵ CFU by eye droppings. At 10⁵ CFU infection dose, the average bacteria content per gram spleen of mice in oral and injection groups was 10^5.673 CFU/g and 10^5.009 CFU/g respectively, and there was no significant difference between them (P>0.05). However, the average weight of spleen was 0.310 g in the oral group, which was significantly higher than 0.165 g in the injection group (P<0.01). During the experimental period, the titers of IgG antibody increased continuously with the increase of infection time in injection and oral groups. Overall, the IgG peak value of oral group was significantly higher than that of injection group. The IgM change trend was coincide between the two groups. Two mice in oral group produced IgA antibody 28 days after infection, but IgA antibody was not detectable in injection group. [Conclusion] This study established the BALB/c mice model infected Brucella abortus strain 2308 by different routes.

Key words:Brucella abortus;mice infection model;the bacteria content per gram of spleen