IHEM, CONICET, Universidad Nacional de Cuyo, Mendoza, Argentina.
Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Cuyo, Mendoza, Argentina.
Front Immunol. 2023 Oct 9;14:1253099. doi: 10.3389/fimmu.2023.1253099. eCollection 2023.
In this work, we aimed at investigating cell and tissue responses of the apple snail , following the inoculation of the zoonotic pathogen . Different doses were tested (10, 20, 65, and 100 M CFU) and the mortality rate was negligible. The histopathogenesis was followed at 4, 9, and 28 days after inoculation. Overt histopathological lesions were consistently observed after the two largest doses only. In the lung, marked hemocyte aggregations, including intravascular nodule formation, were observed within the large blood veins that run along the floor and roof of this organ. Hemocyte aggregations were found occluding many of the radial sinuses supplying the respiratory lamina. Acid-fast bacilli were contained in the different hemocyte aggregations. In addition, hemocytes were observed infiltrating the storage tissue, which makes up most of the lung wall, and the connective tissue of the mantle edge. Additionally, signs of degradation in the storage tissue were observed in the lung wall on day 28. In the kidney, nodules were formed associated with the constitutive hemocyte islets and with the subpallial hemocoelic space, in whose hemocytes the acid-fast structures were found. Electron microscopy analysis revealed the presence of bacteria-containing phagosomes within hemocytes located in the surface zone of the islets. Additionally, electron-dense spheroidal structures, which are likely remnants of digested mycobacteria, were observed in close proximity to the hemocytes' nuclei. The size attained by the hemocyte nodules varied during the observation period, but there was no clear dependence on dose or time after inoculation. Nodules were also formed subpallially. Some of these nodules showed 2-3 layers with different cellular composition, suggesting they may also form through successive waves of circulating cells reaching them. Nodular cores, including those formed intravascularly in the lung, would exhibit signs of hemocyte dedifferentiation, possibly proliferation, and death. Hemocyte congestion was observed in the hemocoelic spaces surrounding the pallial ends of the renal crypts, and the renal crypts themselves showed de-epithelization, particularly on day 28. The diverse cellular responses of to inoculation and the high resilience of this snail to the pathogen make it a suitable species for studying mycobacterial infections and their effects on cellular and physiological processes.
在这项工作中，我们旨在研究在接种人畜共患病原体后，苹果蜗牛的细胞和组织反应。测试了不同剂量（10、20、65 和 100 M CFU），死亡率可忽略不计。接种后 4、9 和 28 天观察组织病理学发病机制。仅在两个最大剂量后始终观察到明显的组织病理学病变。在肺部，沿器官地板和屋顶运行的大静脉内观察到明显的血细胞聚集，包括血管内结节形成。血细胞聚集物阻塞了供应呼吸板的许多径向窦。在不同的血细胞聚集物中发现了抗酸杆菌。此外，还观察到血细胞浸润储存组织，该组织构成了大部分肺壁和套边缘的结缔组织。此外，在第 28 天还观察到肺壁中储存组织的退化迹象。在肾脏中，与固有血细胞胰岛和副神经腔相关的结节形成，在其血细胞中发现了抗酸结构。电子显微镜分析显示，位于胰岛表面区的血细胞内存在含有细菌的吞噬体。此外，还观察到与血细胞核紧密相邻的电子致密球形结构，这些结构可能是消化分枝杆菌的残留物。在观察期间，血细胞结节的大小发生变化，但与接种后的剂量或时间没有明显的依赖关系。副神经腔也形成结节。其中一些结节显示出 2-3 层不同的细胞组成，表明它们也可能通过循环细胞的连续波到达它们而形成。包括在肺部血管内形成的结节核心，将表现出血细胞去分化的迹象，可能是增殖和死亡。围绕肾脏隐窝的套端的血腔中观察到血细胞充血，并且肾脏隐窝本身表现出脱上皮化，特别是在第 28 天。接种后，苹果蜗牛对病原体的细胞和组织反应多种多样，且对病原体具有高弹性，使其成为研究分枝杆菌感染及其对细胞和生理过程的影响的合适物种。
