我们研究了感染T.canis幼虫的小鼠中器官特异性弓形虫幼虫的迁移。我们观察了蠕虫负担和全身免疫反应。三组BALB/c小鼠(每组n=5)口服给药1,000头犬第二阶段幼虫以诱导幼虫迁徙。在感染后1、3和5周处死小鼠。肝脏,肺,大脑,并收集眼组织。每组2只小鼠的组织被消化用于幼虫计数,其余3只小鼠进行组织学分析。评估血液血液学和血清学,并与未感染的对照组(n=5)进行比较,以评估免疫反应。还分析了支气管肺泡灌洗(BAL)液中的细胞因子水平。我们发现,感染后1周,肝脏中的平均寄生虫负荷(72±7.1),脑(31±4.2),肺(20±5.7),和眼睛(2±0)达到峰值并保持恒定,直到3周。感染后5周,肝脏和肺部的蠕虫负担分别显着降低到10±4.2和9±5.7,而它们在大脑和眼睛中保持相对稳定(分别为18±4.2和1±0)。有趣的是,眼幼虫居住在所有视网膜层中,在外视网膜没有明显的炎症。感染T.canis的小鼠表现出中性粒细胞水平升高,单核细胞,嗜酸性粒细胞,免疫球蛋白E在感染后5周,白细胞介素(IL)-5和IL-13水平在BAL液中升高。而BAL液中的IL-4,IL-10,IL-17和干扰素-γ水平与对照组相似。我们的发现表明,在感染的第一周内,一小部分犬只幼虫迁移到眼睛和大脑。观察到最小的组织炎症,可能是由于抗炎细胞因子的增加。这项研究有助于我们了解小鼠对T.canis感染的组织学和免疫学反应,这可能对进一步了解人类弓形虫病有影响。
We investigated organ specific Toxocara canis larval migration in mice infected with T. canis larvae. We observed the worm burden and systemic immune responses. Three groups of BALB/c mice (n=5 each) were orally administered 1,000 T. canis 2nd stage larvae to induce larva migrans. Mice were sacrificed at 1, 3, and 5 weeks post-infection. Liver, lung, brain, and eye tissues were collected. Tissue from 2 mice per group was digested for larval count, while the remaining 3 mice underwent histological analysis. Blood hematology and serology were evaluated and compared to that in a control uninfected group (n=5) to assess the immune response. Cytokine levels in bronchoalveolar lavage (BAL) fluid were also analyzed. We found that, 1 week post-infection, the mean parasite load in the liver (72±7.1), brain (31±4.2), lungs (20±5.7), and eyes (2±0) peaked and stayed constant until the 3 weeks. By 5-week post-infection, the worm burden in the liver and lungs significantly decreased to 10±4.2 and 9±5.7, respectively, while they remained relatively stable in the brain and eyes (18±4.2 and 1±0, respectively). Interestingly, ocular larvae resided in all retinal layers, without notable inflammation in outer retina. Mice infected with T. canis exhibited elevated levels of neutrophils, monocytes, eosinophils, and immunoglobulin E. At 5 weeks post-infection, interleukin (IL)-5 and IL-13 levels were elevated in BAL fluid. Whereas IL-4, IL-10, IL-17, and interferon-γ levels in BAL fluid were similar to that in controls. Our findings demonstrate that a small portion of T. canis larvae migrate to the eyes and brain within the first week of infection. Minimal tissue inflammation was observed, probably due to increase of anti-inflammatory cytokines. This study contributes to our understanding of the histological and immunological responses to T. canis infection in mice, which may have implications to further understand human toxocariasis.