Ek Courtney E, Nosach Roman, Fernando Champika, Huang Yanyun, Perez Jason Byron D S, Costa Matheus O, Ekanayake Samantha, Hill Janet E, Harding John C S
Department of Large Animal Clinical Studies, Saskatoon, SK, Canada.
Department of Veterinary Microbiology, Saskatoon, SK, Canada.
BMC Vet Res. 2017 Aug 22;13(1):261. doi: 10.1186/s12917-017-1166-5.
The development of a mouse model as an in vivo pathogenicity screening tool for Brachyspira spp. has advanced the study of these economically important pathogens in recent years. However, none of the murine models published to date have been used to characterize the clinical signs of disease in mice, instead focusing on pathology following oral inoculation with various Brachyspira spp. The experiments described herein explore modifications of published models to characterize faecal consistency, faecal shedding and pathology in mice challenged with "Brachyspira hampsonii" clade II (Bhamp).
In Experiment 1, 24 CF-1 mice were randomly allocated to one of three inoculation groups: sham (Ctrl), Bhamp, or B. hyodysenteriae (Bhyo; positive control). Half of each group was fed normal mouse chow (RMH) while the other received a low-zinc diet (TD85420). In Experiment 2, eight CF-1 mice and nine C3H/HeN mice were divided into Ctrl or Bhamp inoculation groups, and all fed TD85420. In Experiment 1, mice fed TD85420 demonstrated more severe mucoid faeces (P = 0.001; Kruskal Wallis) and faecal shedding for a significantly greater number of days (P = 0.005; Kruskal Wallis). Mean faecal scores of Bhamp inoculated mice trended higher than Ctrl (P = 0.06; Wilcoxon rank-sum) as did those of Bhyo mice (P = 0.0; Wilcoxon rank-sum). In Experiment 2, mean faecal scores of inoculated CF-1 mice were significantly greater than in C3H mice (P = 0.049; Kruskal Wallis) but no group differences in faecal shedding were observed. In both experiments, mice clustered based on the severity of colonic and caecal histopathology but high lesion scores were not always concurrent with high fecal scores.
In our laboratory, CF-1 mice and the lower-zinc TD85420 diet provide a superior murine challenge model of "Brachyspira hampsonii" clade II.
近年来，将小鼠模型作为短螺旋体属细菌的体内致病性筛选工具的发展推动了对这些具有重要经济意义的病原体的研究。然而，迄今为止发表的所有小鼠模型都未用于描述小鼠疾病的临床症状，而是侧重于口服接种各种短螺旋体属细菌后的病理学研究。本文所述实验探索了对已发表模型的改进，以描述用“汉普森短螺旋体”进化枝II（Bhamp）攻击的小鼠的粪便稠度、粪便排菌情况和病理学特征。
在实验1中，将24只CF-1小鼠随机分配到三个接种组之一：假手术组（Ctrl）、Bhamp组或猪痢疾短螺旋体组（Bhyo；阳性对照组）。每组一半小鼠喂食正常小鼠饲料（RMH），另一半则接受低锌饮食（TD85420）。在实验2中，将8只CF-1小鼠和9只C3H/HeN小鼠分为Ctrl组或Bhamp接种组，所有小鼠均喂食TD85420。在实验1中，喂食TD85420的小鼠表现出更严重的黏液样粪便（P = 0.001；Kruskal Wallis检验），且粪便排菌天数显著更多（P = 0.005；Kruskal Wallis检验）。Bhamp接种组小鼠的平均粪便评分有高于Ctrl组的趋势（P = 0.06；Wilcoxon秩和检验），Bhyo组小鼠也是如此（P = 0.0；Wilcoxon秩和检验）。在实验2中，接种的CF-1小鼠的平均粪便评分显著高于C3H小鼠（P = 0.049；Kruskal Wallis检验），但未观察到粪便排菌情况存在组间差异。在两个实验中,小鼠根据结肠和盲肠组织病理学的严重程度聚类，但高病变评分并不总是与高粪便评分同时出现。
在我们的实验室中，CF-1小鼠和低锌TD85420饮食提供了一种更优的“汉普森短螺旋体”进化枝II小鼠攻击模型。
