Silva-Dos-Santos Danielle, Barreto-de-Albuquerque Juliana, Guerra Bárbara, Moreira Otacilio C, Berbert Luiz Ricardo, Ramos Mariana Tavares, Mascarenhas Barbara Angelica S, Britto Constança, Morrot Alexandre, Serra Villa-Verde Déa M, Garzoni Luciana Ribeiro, Savino Wilson, Cotta-de-Almeida Vinícius, de Meis Juliana
Laboratory on Thymus Research, Oswaldo Cruz Institute, Oswaldo Cruz Foundation, Rio de Janeiro, Brazil.
National Center of Structural Biology and Bio-imaging-CENABIO, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil.
PLoS Negl Trop Dis. 2017 Apr 5;11(4):e0005507. doi: 10.1371/journal.pntd.0005507. eCollection 2017 Apr.
Oral transmission of Trypanosoma cruzi, the causative agent of Chagas disease, is the most important route of infection in Brazilian Amazon and Venezuela. Other South American countries have also reported outbreaks associated with food consumption. A recent study showed the importance of parasite contact with oral cavity to induce a highly severe acute disease in mice. However, it remains uncertain the primary site of parasite entry and multiplication due to an oral infection. Here, we evaluated the presence of T. cruzi Dm28c luciferase (Dm28c-luc) parasites in orally infected mice, by bioluminescence and quantitative real-time PCR. In vivo bioluminescent images indicated the nasomaxillary region as the site of parasite invasion in the host, becoming consistently infected throughout the acute phase. At later moments, 7 and 21 days post-infection (dpi), luminescent signal is denser in the thorax, abdomen and genital region, because of parasite dissemination in different tissues. Ex vivo analysis demonstrated that the nasomaxillary region, heart, mandibular lymph nodes, liver, spleen, brain, epididymal fat associated to male sex organs, salivary glands, cheek muscle, mesenteric fat and lymph nodes, stomach, esophagus, small and large intestine are target tissues at latter moments of infection. In the same line, amastigote nests of Dm28c GFP T. cruzi were detected in the nasal cavity of 6 dpi mice. Parasite quantification by real-time qPCR at 7 and 21 dpi showed predominant T. cruzi detection and expansion in mouse nasal cavity. Moreover, T. cruzi DNA was also observed in the mandibular lymph nodes, pituitary gland, heart, liver, small intestine and spleen at 7 dpi, and further, disseminated to other tissues, such as the brain, stomach, esophagus and large intestine at 21 dpi. Our results clearly demonstrated that oral cavity and adjacent compartments is the main target region in oral T. cruzi infection leading to parasite multiplication at the nasal cavity.
克氏锥虫是恰加斯病的病原体，经口传播是巴西亚马逊地区和委内瑞拉最重要的感染途径。其他南美国家也报告了与食物消费相关的疫情爆发。最近一项研究表明，寄生虫与口腔接触对于在小鼠中引发高度严重的急性疾病具有重要意义。然而，由于经口感染，寄生虫进入和增殖的主要部位仍不确定。在此，我们通过生物发光和定量实时PCR评估了经口感染小鼠中克氏锥虫Dm28c荧光素酶（Dm28c-luc）寄生虫的存在情况。体内生物发光图像显示鼻上颌区域是寄生虫在宿主体内的入侵部位，在整个急性期持续受到感染。在感染后的后期，即感染后7天和21天，由于寄生虫在不同组织中的扩散，胸部、腹部和生殖区域的发光信号更强。离体分析表明，鼻上颌区域、心脏、下颌淋巴结、肝脏、脾脏、大脑、与雄性性器官相关的附睾脂肪、唾液腺、颊肌、肠系膜脂肪和淋巴结、胃、食管、小肠和大肠是感染后期的靶组织。同样，在感染后6天的小鼠鼻腔中检测到了克氏锥虫Dm28c GFP的无鞭毛体巢。在感染后7天和21天通过实时定量PCR进行的寄生虫定量显示，在小鼠鼻腔中主要检测到克氏锥虫并出现增殖。此外，在感染后7天，在下颌淋巴结、垂体、心脏、肝脏、小肠和脾脏中也观察到了克氏锥虫DNA，并且在感染后21天进一步扩散到其他组织，如大脑、胃、食管和大肠。我们的结果清楚地表明，口腔及相邻区域是经口感染克氏锥虫导致寄生虫在鼻腔增殖的主要靶区域。
