Laboratory of Apoptosis, Department of General Pathology, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil.
Vet Parasitol. 2012 Oct 26;189(2-4):162-70. doi: 10.1016/j.vetpar.2012.04.035. Epub 2012 May 3.
The skin has an important role in infection by Leishmania chagasi. Apoptosis modulates the inflammatory response acting distinctively either on the progression or regression of the lesions. The parasites interact with multiple regulatory systems inducing apoptosis in host cells, during cell invasion, stabilization and multiplication of pathogens. In this context, the aim of this study was to evaluate cell death within the inflammatory infiltrates, and to correlate these results with parasite load and clinical features of dogs naturally infected with L. chagasi. Fragments of skin pinnas (8 symptomatic+8 asymptomatic+6 negative controls) were used to characterize and measure the inflammatory response, parasite load and apoptosis. Diagnosis of canine leishmaniasis was confirmed by the detection of anti-Leishmania antibodies by IFA and ELISA in serum, direct visualization of the parasite and culture in spleen, liver, pinna, bone marrow and lymph nodes, and PCR (pinna). Histomorphometry was performed with images obtained from 20 representative histological fields in a light microscope. Ultra-thin sections were mounted over a 300 mesh grids, contrasted with 2% uranyl acetate and lead citrate and examined under a Transmission Electronic Microscopy. Amastigotes were only found in the skin of symptomatic animals (31.94 ± 18.81). The number of foci and cellularity of the inflammatory infiltrates in symptomatic dogs were higher than in other groups and in asymptomatics were higher than in controls (p<0.05; Tukey). The average area, perimeter and extreme diameters of the inflammatory infiltrates obtained in symptomatic dogs were higher than in controls (p<0.05; Tukey). The apoptotic index was higher in symptomatic than in other groups and there was no difference between asymptomatics and controls (p<0.05; Tukey). Ultrastructurally, apoptotic cells were shrunken, with condensed nuclear chromatin and cytoplasm. Condensed nuclei were frequently fragmented. Internucleosomal DNA fragmentation occurred only in symptomatic cases. Amastigotes were observed within neutrophils and macrophages. Apoptosis is directly related to parasite load, intensity of inflammatory response and clinical manifestations in L. chagasi naturally infected dogs.
皮肤在感染恰加斯锥虫中具有重要作用。细胞凋亡调节炎症反应，对病变的进展或消退有明显的作用。寄生虫与多个调节系统相互作用，在宿主细胞入侵、病原体稳定和增殖过程中诱导细胞凋亡。在这种情况下，本研究的目的是评估炎症浸润中的细胞死亡，并将这些结果与犬自然感染恰加斯锥虫的寄生虫载量和临床特征相关联。使用皮肤 pinnas 片段（8 个有症状+8 个无症状+6 个阴性对照）来表征和测量炎症反应、寄生虫载量和细胞凋亡。通过血清中的 IFA 和 ELISA 检测抗莱什曼原虫抗体、寄生虫的直接观察以及脾、肝、 pinnas、骨髓和淋巴结的培养和 PCR（pinnas）来确认犬利什曼病的诊断。通过在光显微镜下获得的 20 个有代表性的组织学视野进行组织形态计量学。将超薄切片安装在 300 目网格上，用 2%醋酸铀和柠檬酸铅进行对比，并在透射电子显微镜下进行检查。仅在有症状动物的皮肤中发现无鞭毛体（31.94±18.81）。有症状犬的炎症浸润灶数量和细胞密度高于其他组，无症状犬高于对照组（p<0.05；Tukey）。有症状犬获得的炎症浸润平均面积、周长和极值直径均高于对照组（p<0.05；Tukey）。与其他组相比，有症状组的细胞凋亡指数更高，无症状组与对照组之间没有差异（p<0.05；Tukey）。超微结构上，凋亡细胞体积缩小，核染色质和细胞质浓缩。核常碎裂。只有在有症状的病例中才观察到核小体间 DNA 片段化。无鞭毛体在中性粒细胞和巨噬细胞内被观察到。细胞凋亡与恰加斯锥虫自然感染犬的寄生虫载量、炎症反应强度和临床表现直接相关。
