Instituto de Medicina Molecular-João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal.
Department of Neuroscience, University of Texas Southwestern Medical Center, Dallas, TX, United States of America.
PLoS Negl Trop Dis. 2018 Aug 15;12(8):e0006690. doi: 10.1371/journal.pntd.0006690. eCollection 2018 Aug.
African trypanosomiasis is caused by the protozoan parasite Trypanosoma brucei, transmitted between mammals by the bite of a tsetse. It has been recently shown that parasites accumulate in large numbers in various organs and tissues, including the mouse testis. Whether parasites are protected from the immune system in the male reproductive organ or can be transmitted through sexual route remains unknown. Here we show that parasites can be detected by fine needle aspiration cytology of the male reproductive system in mice, and histopathological analysis revealed that T. brucei accumulates in the stroma of the epididymis, epididymal adipose tissue and fibrous tunics of the testis. No parasites were found in the lumen of intact epididymal ducts or seminiferous tubules of the testis, indicating that the large majority of the parasites are not located in immune-privileged sites. In fact, these parasites are associated with marked inflammatory cell infiltration, parasite degeneration, and severe tissue damage and rupture of epididymal ducts, which may be related with reduced fertility. Overall, we show that just like in the bloodstream and most other tissues, in the male reproductive organs, T. brucei are exposed to a strong immune response. The detection of a very high number of parasites in this organ and its accessibility opens the possibility of using fine needle aspiration cytology as a complementary diagnostic tool in Animal African Trypanosomiasis.
非洲锥虫病是由原生动物寄生虫布氏锥虫引起的，通过采采蝇叮咬在哺乳动物之间传播。最近有研究表明，寄生虫在各种器官和组织中大量积累，包括小鼠睾丸。寄生虫是否在雄性生殖器官中免受免疫系统的保护，或者是否可以通过性途径传播仍然未知。在这里，我们展示了可以通过小鼠生殖系统的细针抽吸细胞学检测到寄生虫，并且组织病理学分析显示，布氏锥虫在附睾的基质、附睾脂肪组织和睾丸的纤维鞘中积累。在完整的附睾管或睾丸的生精小管的管腔中未发现寄生虫，表明绝大多数寄生虫不在免疫特权部位。事实上，这些寄生虫与明显的炎症细胞浸润、寄生虫退化以及附睾管的严重组织损伤和破裂有关，这可能与生育能力降低有关。总的来说，我们表明，就像在血液和大多数其他组织中一样，在雄性生殖器官中，布氏锥虫受到强烈的免疫反应的影响。在这个器官中检测到大量寄生虫，并使其具有可及性，为使用细针抽吸细胞学作为动物非洲锥虫病的补充诊断工具提供了可能性。
