Increased susceptibility to encephalitozoonosis associated with mixed Th1/Th2 profile and M1/M2 profile in mice immunosuppressed with cyclophosphamide.

Encephalitozoon cuniculi is a unicellular, spore-forming, obligate intracellular eukaryote belonging to the phylum Microsporidia. It is known to infect mainly immunocompromised and immunocompetent mammals, including humans. The parasite-host relationship has been evaluated using both in vitro cell culturing and animal models. For example, Balb/c and C57BL/6 mouse strains have been used interchangeably, although the latter has been considered more susceptible due to the higher fungal load observed after infection. In the present study, we identified the characteristics of the immune response of C57BL/6 mice treated or not with the immunosuppressant cyclophosphamide (Cy) and challenged with E. cuniculi by intraperitoneal route. After 14 days of infection, serum was collected to analyze Th1, Th2, and Th17 cytokine levels. In addition, peritoneal washes were performed, and the spleen sample was collected for immune cell phenotyping, whereas liver, spleen, kidney, lung, intestine, and central nervous system (CNS) samples were collected for histopathological analysis. Although infected mice displayed a reduced absolute number of macrophages, they showed an M1 profile, an elevated number of CD4+T, CD8+T, B-1, and B-2 lymphocytes, with a predominance of Th1 inflammatory cytokines (interferon [IFN]-γ, tumor necrosis factor [TNF]-α, and interleukin [IL]-2) and Th17. Furthermore, Cy-Infected mice showed a reduced absolute number of macrophages with an M1 profile but a reduced number of CD4+T, CD8+T, B-1, and B-2 lymphocytes, with a predominance of Th1 inflammatory cytokines (IFN-γ, TNF-α, and IL-2) and Th2 (IL-4). This group displayed a higher fungal burden as well and developed more severe encephalitozoonosis, which was associated with a reduced number of T and B lymphocytes and a mixed profile of Th1 and Th2 cytokines.

Distribution of M1 and M2 macrophages in cerebral granulomas caused by Encephalitozoon cuniculi.

Encephalitozoon cuniculi spores cause severe granulomatous inflammation in the brain where mononuclear cells and macrophages infiltrate. Here, we orally infected New Zealand white rabbits with 1 × 106E. cuniculi viable spores to study the recruitment and localization of macrophages in brain granulomas. At day 30 post-infection, the positive phenotype markers iNOS (M1) and Arg-1 (M2) were located in the periphery and center of granulomas, respectively. Live intracytoplasmic spores were found only in positive Arg-1 cells. This is the first work to describe the recruitment and distribution of M1 and M2 macrophages in the brain granulomas of rabbits infected with E. cuniculi.

Opportunistic pneumonia caused by E. cuniculi in mice immunosuppressed with cyclophosphamide.

Opportunistic fungal pneumonia is a cause of concern in immunocompromised patients due to its high morbidity and mortality rates. One such opportunistic agent affecting immunocompromised patients is the microsporidia called Encephalitozoon cuniculi. This study aimed to evaluate pneumonia caused by E. cuniculi in mice treated with the immunosuppressive agent cyclophosphamide (Cy). This study also aimed to describe the immune cells associated with the microsporidial pneumonia. C57BL/6 mice were infected intravenously with E. cuniculi spores and treated with Cy (75 mg/kg/week, intraperitoneally). Thirty days post-infection, the fungal burden (qPCR), histopathological lesions, cytokine production, and the phenotype of the immune cells in the lung parenchyma were evaluated. Histologically, interstitial pneumonia with lymphocytic infiltrate was observed in the infected animals. The infiltrate mainly consisted of CD8+ and CD4+ T lymphocytes, with reduced populations of B lymphocytes and macrophages. The production of tumor necrosis factor-alpha (TNF-α) was significant in the animals of the infected groups. Also, the fungal burden was higher in the Cy-treated animals, which was confirmed by the immunohistochemical observation of spores. These results demonstrated that E. cuniculi infection of C57BL/6 mice caused lymphocytic interstitial pneumonia (characterized by a predominant lymphocytic infiltrate), which was aggravated by Cy-induced immunosuppression. Thus, these results can be used to understand the different pathological, immunological, and therapeutic aspects of lymphocytic interstitial pneumonia.

Mice with genetic and induced B-cell deficiency as a model for disseminated encephalitozoonosis.

Encephalitozoon cuniculi, an intracellular pathogen, lives in a balanced relationship with immunocompetent individuals based on the activity of T lymphocytes. We previously highlighted the greater susceptibility of B-1 cell-deficient mice (XID mice) to encephalitozoonosis. This study aimed to develop a model of disseminated and severe encephalitozoonosis in mice with combined immunodeficiency to elucidate the role of B cells. To address this objective, cyclophosphamide (Cy)-treated BALB/c and XID mice were inoculated with E. cuniculi, followed by the evaluation of the immune response and histopathological lesions. Immunosuppressed BALB/c mice manifested no clinical signs with an increase in the populations of T lymphocytes and macrophages in the spleen. Immunosuppressed and infected XID mice revealed elevated T cells, macrophages populations, and pro-inflammatory cytokines levels (IFN-γ, TNF-α, and IL-6) with the presence of abdominal effusion and lesions in multiple organs. These clinical characteristics are associated with extensive and severe encephalitozoonosis. The symptoms and lesion size were reduced, whereas B-2 and CD4+ T cells populations were increased in the spleen by transferring B-2 cells adoptive to XID mice. Moreover, B-1 cells adoptive transfer upregulated the peritoneal populations of B-2 cells and macrophages but not T lymphocytes and decreased the symptoms. Herein, we speculated the consistency in the development of severe and disseminated encephalitozoonosis in mice with genetic deficiency of Bruton's tyrosine kinase (Btk) associated with Cy immunosuppression develop with that of the models with T cell deficiency. Taken together, these data emphasized the crucial role of B cells in the protective immune response against encephalitozoonosis.

Opportunistic pneumonia caused by E. cuniculi in mice immunosuppressed with cyclophosphamide

Opportunistic fungal pneumonia is a cause of concern in immunocompromised patients due to its high morbidity and mortality rates. One such opportunistic agent affecting immunocompromised patients is the microsporidia called Encephalitozoon cuniculi. This study aimed to evaluate pneumonia caused by E. cuniculi in mice treated with the immunosuppressive agent cyclophosphamide (Cy). This study also aimed to describe the immune cells associated with the microsporidial pneumonia. C57BL/6 mice were infected intravenously with E. cuniculi spores and treated with Cy (75 mg/kg/week, intraperitoneally). Thirty days post-infection, the fungal burden (qPCR), histopathological lesions, cytokine production, and the phenotype of the immune cells in the lung parenchyma were evaluated. Histologically, interstitial pneumonia with lymphocytic infiltrate was observed in the infected animals. The infiltrate mainly consisted of CD8+ and CD4+ T lymphocytes, with reduced populations of B lymphocytes and macrophages. The production of tumor necrosis factor-alpha (TNF-α) was significant in the animals of the infected groups. Also, the fungal burden was higher in the Cy-treated animals, which was confirmed by the immunohistochemical observation of spores. These results demonstrated that E. cuniculi infection of C57BL/6 mice caused lymphocytic interstitial pneumonia (characterized by a predominant lymphocytic infiltrate), which was aggravated by Cy-induced immunosuppression. Thus, these results can be used to understand the different pathological, immunological, and therapeutic aspects of lymphocytic interstitial pneumonia.

Mice with genetic and induced B-cell deficiency as a model for disseminated encephalitozoonosis

Encephalitozoon cuniculi, an intracellular pathogen, lives in a balanced relationship with immunocompetent individuals based on the activity of T lymphocytes. We previously highlighted the greater susceptibility of B-1 cell-deficient mice (XID mice) to encephalitozoonosis. This study aimed to develop a model of disseminated and severe encephalitozoonosis in mice with combined immunodeficiency to elucidate the role of B cells. To address this objective, cyclophosphamide (Cy)-treated BALB/c and XID mice were inoculated with E. cuniculi, followed by the evaluation of the immune response and histopathological lesions. Immunosuppressed BALB/c mice manifested no clinical signs with an increase in the populations of T lymphocytes and macrophages in the spleen. Immunosuppressed and infected XID mice revealed elevated T cells, macrophages populations, and pro-inflammatory cytokines levels (IFN-γ, TNF-α, and IL-6) with the presence of abdominal effusion and lesions in multiple organs. These clinical characteristics are associated with extensive and severe encephalitozoonosis. The symptoms and lesion size were reduced, whereas B-2 and CD4+ T cells populations were increased in the spleen by transferring B-2 cells adoptive to XID mice. Moreover, B-1 cells adoptive transfer upregulated the peritoneal populations of B-2 cells and macrophages but not T lymphocytes and decreased the symptoms. Herein, we speculated the consistency in the development of severe and disseminated encephalitozoonosis in mice with genetic deficiency of Bruton’s tyrosine kinase (Btk) associated with Cy immunosuppression develop with that of the models with T cell deficiency. Taken together, these data emphasized the crucial role of B cells in the protective immune response against encephalitozoonosis.

Encefalitozoonose em coelho (Oryctolagus cuniculus) / Encephalitozoonosis in rabbit (Oryctolagus cuniculus)

Background: Encephalitozoonosis is caused by the protozoan Encephalitozoon cuniculi, in rabbits, and can affect humans. The disease can be fatal and difficult to diagnose. It can be asymptomatic or cause vestibular neurological disease, paralysis, uveitis in addition to chronic kidney disease in rabbits. The transmission of the microorganism's spores occurs by ingestion, inhalation, or by the transplacental route. The aim of this work is to report a case of encephalitozoonosis in a pet rabbit (Oryctolagus cuniculus). Case: An Oryctolagus cuniculus with a history of paraparesis of the thoracic and pelvic limbs was referred for necropsy, the evolution of the clinical picture happened in one day. After death, a necropsy was performed. Organ fragments were collected, fixed, and processed routinely for histology. Macroscopically, there was evidence of hepatic lobes, without injury to the other organs. Microscopically it was observed in the white and gray substance of the telencephalon multiple circumscribed granulomas composed of a necrotic center surrounded by macrophages, giant multinucleated cells in addition to lymphocytes and plasmocytes in the periphery, delimited by fibrous connective tissue. Around the vessels, perivascular cuffs with 2 to 4 layers of lymphocytic infiltrate were observed. Besides, special staining of Schiff's Periodic Acid (PAS) and Ziehl-Neelsen was performed, in which numerous cylindrical, eosinophilic structures of approximately 2.5 x 1.0 µm were observed, compatible with E. cuniculi spores. Besides, histiocytic lymphoblasts pericoronitis was noted in the liver. There were no relevant changes in the kidney. Discussion: The diagnosis of encephalitozoonosis in rabbits was based on clinical and anatomopathological findings. Tetraparesis was the predominant sign in the present case and was justified by telencephalic lesions. This clinical sign is included in the literature but is less common than the syndrome such as head tilt and paralysis. The diagnosis of the disease is usually made by post mortem examination when it is possible to identify the spores in the lesions. Multifocal granulomatous encephalitis was the most significant finding in this case, which is also consistent with other studies. The pathogenesis of granulomatous lesions is still controversial. It is known that spores allow phagocytosis by macrophages, which induce the production of interleukins and other cytokines by TCD4 + lymphocytes, thereby activating the action of TCD8 + (cytotoxic) lymphocytes. Natural killer cells, granulocytes, other macrophages, and B lymphocytes are also recruited. Although there is such an inflammatory response, the antibodies produced are not efficient to eliminate the agent from the host organism, however, they contribute to the process of opsonization and consequent phagocytosis, facilitating the destruction of the microsporidium by macrophages. The neurological form was predominant in this case, with no chronic or ocular renal forms, possibly due to the rapid clinical evolution. Special stains were useful for visualizing intralesional spores. Although PAS staining is considered to be of little use, it was relevant in this case. The visualization of the agent made it possible to distinguish differential diagnoses, among them vestibular syndrome secondary to otitis due to pasteurellosis, toxoplasmosis, neoplasms, traumas, or diseases of the spine. Thus, a diagnosis of encephalitozoonosis was made in a rabbit through clinical and anatomopathological correlation using Ziehl-Neelsen and PAS stains.

Immunohistochemical localization of TNF-α and IL-4 in granulomas of immunocompetent and immunosuppressed New Zealand white rabbits infected with Encephalitozoon cuniculi.

Encephalitozoon cuniculi is a fungi-related, obligate, zoonotic, spore-forming intracellular eukaryotic microorganism. This emerging pathogen causes granulomas to form in the brain and kidneys of infected individuals. The objective of the current study was to detect the distribution of TNF-α- and IL-4-positive cells using immunohistochemistry within these granulomas in both infected immunocompetent (group A) and immunosuppressed (group B) New Zealand white rabbits. In the brain, labeled TNF-α immune cells were mainly located in the granuloma peripheries in group B. Granulomas examined in the kidneys of groups A and B were TNF-α positive, but were significantly different (p < 0.001) when compared with the brain. IL-4-producing immune cells in the brain and kidneys were disseminated within granulomas in groups A and B; however, no significant difference (p > 0.05), was observed. IL-4 positive cells were more numerous in brain sections of group B and differed significantly (p < 0.05) when compared with kidneys. Granulomas were not observed in control animals (groups C and D). In conclusion, we identified TNF-α positive cells in both the brain and kidneys of immunocompetent and immunosuppressed animals; IL-4 positive cells were numerous in the brains of immunosuppressed rabbits; however, in terms of percentage were numerous in the brains of immunocompetent rabbits. Immunosuppression appeared to stimulate a change in the cellular phenotype of Th1- to Th2-like granulomas in the brain and kidneys via an unknown mechanism. Expression of pro- and pre-inflammatory cytokines in microsporidian granulomas suggests a mechanism by which E. cuniculi evades the immune response, causing more severe disease. These results increase our understanding of TNF-α and IL-4-positive cells within the E. cuniculi granuloma microenvironment.

Variation of the CD4, CD8, and MHC II cell population in granulomas of immunocompetent and immunosuppressed rabbits in Encephalitozoon cuniculi infection.

Encephalitozoon cuniculi (E. cuniculi) is a fungi-related, obligate, zoonotic, spore-forming intracellular eukaryotic microorganism. This emerging pathogen causes granulomas in brain and kidneys of infected individuals. The objective of this study was to detect the distribution of CD4, CD8 and MHCII-positive cells within granulomas in these organs in infected immunocompetent (group A) and infected immunosuppressed (group B) New Zealand white rabbits using immunohistochemistry. In brain, labeled CD4 immune cells were mainly located in the periphery of granulomas in group B. Kidneys of groups A and B, displayed CD4-positive in granulomas and were significant different when compared to brain. CD8 immune cells in brain and kidneys were disseminated in the granulomas in groups A and B; however, no significant difference was observed. MHCII-positive cells were more numerous in brain sections of group B and were significantly different when compared to kidney sections. Granulomas were not observed in control animals of group C and D. In conclusion, we identified CD4-positive cells in both the brain and kidneys of immunocompetent and immunosuppressed animals; CD8-positive cells were more numerous in brain of immunosuppressed rabbits and MHCII cells were more predominant in brain of immunocompetent rabbits. Apparently, the immunosuppression stimulated a change in the cellular phenotype of Th1- to Th2-like granulomas in brain and kidneys by an unknown mechanism. These results increase our understanding of CD4, CD8 and MHCII positive cells within the E. cuniculi granuloma microenvironment and will help in future microsporidian granulomas studies of both immunocompetent and immunosuppressed individuals.

Increased phagocytosis and growth inhibition of Encephalitozoon cuniculi by LPS-activated J774A.1 murine macrophages.

Encephalitozoon cuniculi is an obligate macrophage parasite of vertebrates that commonly infects rodents, monkeys, dogs, birds, and humans. In the present study, we aimed to assess the phagocytosis and intracellular survival of E. cuniculi spores using untreated and lipopolysaccharide (LPS)-activated J774A.1 murine macrophages and assess the macrophage viability. The experimental groups comprised untreated spores, spores killed by heat treatment at 90 °C, and spores killed by treatment with 10% formalin. LPS-activated macrophages significantly increased the phagocytosis of spores and reduced their intracellular growth after 24 and 48 h (P < 0.01); however, after 72 h, we observed an increase in spore replication but no detectable microbicidal activity. These results indicate that LPS activation enhanced E. cuniculi phagocytosis between 24 and 48 h of treatment, but the effect was lost after 72 h, enabling parasitic growth. This study contributes to the understanding of the phagocytosis and survival of E. cuniculi in murine macrophages.

Quantitative analysis of TNF-α, IL-4, and IL-10 expression, nitric oxide response, and apoptosis in Encephalitozoon cuniculi-infected rabbits.

The expression of tumor necrosis factor (TNF) -α, interleukin (IL) -4 and IL-10, as well as apoptosis and nitric oxide (NO) levels were measured in the brain and kidneys of immunocompetent and immunosuppressed New Zealand White rabbits infected with Encephalitozoon cuniculi. All of the animals had clinical signs histopathological lesions compatible with encephalitozoonosis and were E. cuniculi-positive by using a carbon immunoassay test. Encephalitozoon cuniculi infection promoted the expression of TNF-α and NO production in the kidneys of infected rabbits, and a synergic effect was observed in animal treated with dexamethasone. The IL-4 expression was similar in the brain and kidneys of infected rabbits, regardless of their immunologic status. The IL-10 mRNA expression in the brain of infected immunosuppressed rabbits was elevated when compared with positive controls. Apoptosis of granuloma mononuclear-like cells was detected in immunocompetent E. cuniculi-infected rabbits, but it was more evident in infected-immunosuppressed animals. Nitric oxide levels were elevated both in immunocompetent and immunosuppressed infected animals, but it was more apparent in the kidneys. These data suggest that modulation of the immune response by E. cuniculi could contribute to the survival of the parasite within phagocytic cells in granulomas via an as yet undetermined mechanism.

Histochemical study of Encephalitozoon cuniculi spores in the kidneys of naturally infected New Zealand rabbits.

Encephalitozoon cuniculi is an important microsporidian pathogen that is considered an emergent, zoonotic, and opportunistic. It infects both domestic and laboratory rabbits, generating severe chronic interstitial and granulomatous nephritis with fibrosis and granulomatous encephalitis. Encephalitozoonosis is diagnosed in paraffin-embedded sections by examining the spores in the host tissues. The spores are difficult to observe when the samples are stained with hematoxylin and eosin (H&E), particularly when there is an inflammatory reaction and tissue damage. The spores are easily mistaken for other microorganisms, such as fungi (yeasts), protozoa, and bacteria. In our study, we used kidney samples from E. cuniculi-positive rabbits and employed 14 recommended histologic stains for detecting microsporidia spores: alcian blue, calcofluor white, Giemsa, Gram, Grocott, H&E, Luna, Luxol fast blue, Masson trichrome, modified trichrome stain (MTS), periodic acid-Schiff reaction (PAS), Van Gieson, Warthin-Starry (WS), and Ziehl-Neelsen (ZN).We concluded that MTS and Gram stain, detected by light microscopy, and calcofluor white stain, detected by ultraviolet light microscopy, are the best stains for detecting spores of E. cuniculi in paraffin-embedded tissues from infected rabbits. These stains were superior to WS, ZN, Giemsa, and PAS for identifying spores without background "noise" or monochromatic interference. Also, they allow individual spores to be discerned in paraffin-embedded tissues. MTS allows observation of the polar tube, polaroplast, and posterior vacuole, the most distinctive parts of the spore.

B-1 cell decreases susceptibility to encephalitozoonosis in mice.

Encephalitozoon cuniculi is an opportunist intracellular pathogen of mammals. The adaptive immune response is essential to eliminate E. cuniculi, but evidence is mounting that the response initiated by the innate immune response may ultimately define whether or not the parasite can survive. B-1 cells may act as antigen-presenting cells or differentiate into phagocytes, playing different roles in many infection models. However, the role of these cells in the dynamics of Encephalitozoon sp. infections is still unknown. To investigate the role of B-1 cells in E. cuniculi infection, BALB/c and BALB/c XID (B-1 cells deficient) mice were infected with E. cuniculi spores. Cytometric analyses of peritoneal cells showed that B-1 cells and macrophages increased significantly in infected BALB/c mice compared to uninfected controls. Despite the increase in the number of CD4+ and CD8+ lymphocytes in XID mice, these animals were more susceptible to infection as evidenced histologically with more prominent inflammatory lesions and parasite burden. Pro-inflammatory cytokines increased in both infected BALB/c and BALB/c XID mice. To confirm B-1 cells role in encephalitozoonosis, we adoptively transferred B-1 cells to BALB/c XID mice and this group showed few symptoms and microscopic lesions, associated with an increased in cytokines. Together, these results suggest that B-1 cells may increase the resistance of BALB/c mice to encephalitozoonosis, evidencing for the first time the important role of B-1 lymphocytes in the control of microsporidia infection.

Interferon γ and interleukin 10 responses in immunocompetent and immunosuppressed New Zealand White rabbits naturally infected with Encephalitozoon cuniculi.

Levels of interferon (IFN)-γ and interleukin (IL)-10 were measured in the serum of immunocompetent and immunosuppressed New Zealand White rabbits naturally infected with Encephalitozoon cuniculi. IFN-γ levels were elevated in infected rabbits, and a synergic effect was observed in animals treated with the immunosuppressive agent dexamethasone (Dex). The role of IL-10 in infected rabbits remains unclear, as IL-10 levels were similar to those of negative controls. Dex appeared to exhibit a proinflammatory effect, as IFN-γ levels were elevated in infected immunosuppressed rabbits. Similarly, Dex exhibited a synergic effect in infected immunosuppressed rabbits, as evidenced by the elevation in IFN-γ production. These data indicate that the immune response to this glucocorticoid should be considered in the design of future animal model studies of immunosuppression.

Técnicas de coloração para detecção de Encephalitozoon cuniculi em cortes histológicos / Stain techniques for detection of Encephalitozoon cuniculi in tissue sections

No presente trabalho, foram avaliadas diferentes técnicas de coloração aplicadas a cortes histológicos para a identificação de Encephalitozoon cuniculi. Foram utilizados fragmentos hepáticos de camundongos Balb-c, imunossuprimidos com ciclofosfamida e inoculados com esporos de Encephalitozoon cuniculi. Os cortes histológicos incluídos em parafina foram corados pelas técnicas de hematoxilina-eosina (H-E), tricrômica modificada, Gram-Chromotrope, Giemsa, Brown-Hopps, PAS, Ziehl-Neelsen e Grocott, e ainda pela técnica de calcoflúor. As colorações azul de toluidina-fucsina e azul de toluidina foram utilizadas para os cortes incluídos em resina plástica. As técnicas de Gram-Chromotrope, Brown-Hopps e Ziehl-Neelsen foram as que permitiram melhor visualização dos esporos para o diagnóstico de E. cuniculi em cortes histológicos incluídos em parafina, uma vez que possibilitaram a clara diferenciação dos esporos de outras estruturas teciduais. Nos tecidos incluídos em resina plástica, as colorações de azul de toluidina-fucsina e azul de toluidina também facilitaram o encontro do agente. Por outro lado, a técnica tricrômica apresentou grande variabilidade nos resultados, sendo, portanto, pouco indicada para o diagnóstico em tecido. As demais técnicas - H-E, calcoflúor, Grocott, Giemsa e PAS - não permitiram a fácil identificação do E. cuniculi.

In this study, it was investigated different staining techniques applied to histological sections for identification of Encephalitozoon cuniculi. It was used liver fragments from Balb-c mice immunosuppressed with cyclophosphamide and inoculated with spores of Encephalitozoon cuniculi. The histological paraffin embedded sections were stained with hematoxylin-eosin (H-E), modified trichrome, Gram-Chromotrope, Giemsa, Brown-Hopps, PAS, Ziehl-Neelsen, and Grocott and also by the technique of calcofluor. Toluidine blue-fuchsin and toluidine blue stainings were used for the cuts embedded in plastic resin. Gram-Chromotrope, Brown-Hopps and Ziehl-Neelsen staining techniques permitted the best visualization of the spores for the diagnosis of E. cuniculi in histological paraffin embedded sections, since they allowed the clear differentiation of the spores among other tissue structures. In tissues embedded in plastic resin, toluidine blue-fuchsin and toluidine blue stainings also facilitate the finding of the agent. On the other hand, the trichrome technique showed great variability on results, therefore, allowing the identification of the parasite in tissue. The other techniques, H-E, calcofluor, Grocott, Giemsa and PAS did not permited the easy identification of the E. cuniculi spores.

Técnicas de coloração para detecção de Encephalitozoon cuniculi em cortes histológicos

In this study, it was investigated different staining techniques applied to histological sections for identification of Encephalitozoon cuniculi. It was used liver fragments from Balb-c mice immunosuppressed with cyclophosphamide and inoculated with spores of Encephalitozoon cuniculi. The histological paraffin embedded sections were stained with hematoxylin-eosin (H-E), modified trichrome, Gram-Chromotrope, Giemsa, Brown-Hopps, PAS, Ziehl-Neelsen, and Grocott and also by the technique of calcofluor. Toluidine blue-fuchsin and toluidine blue stainings were used for the cuts embedded in plastic resin. Gram-Chromotrope, Brown-Hopps and Ziehl-Neelsen staining techniques permitted the best visualization of the spores for the diagnosis of E. cuniculi in histological paraffin embedded sections, since they allowed the clear differentiation of the spores among other tissue structures. In tissues embedded in plastic resin, toluidine blue-fuchsin and toluidine blue stainings also facilitate the finding of the agent. On the other hand, the trichrome technique showed great variability on results, therefore, allowing the identification of the parasite in tissue. The other techniques, H-E, calcofluor, Grocott, Giemsa and PAS did not permited the easy identification of the E. cuniculi spores.

No presente trabalho, foram avaliadas diferentes técnicas de coloração aplicadas a cortes histológicos para a identificação de Encephalitozoon cuniculi. Foram utilizados fragmentos hepáticos de camundongos Balb-c, imunossuprimidos com ciclofosfamida e inoculados com esporos de Encephalitozoon cuniculi. Os cortes histológicos incluídos em parafina foram corados pelas técnicas de hematoxilina-eosina (H-E), tricrômica modificada, Gram-Chromotrope, Giemsa, Brown-Hopps, PAS, Ziehl-Neelsen e Grocott, e ainda pela técnica de calcoflúor. As colorações azul de toluidina-fucsina e azul de toluidina foram utilizadas para os cortes incluídos em resina plástica. As técnicas de Gram-Chromotrope, Brown-Hopps e Ziehl-Neelsen foram as que permitiram melhor visualização dos esporos para o diagnóstico de E. cuniculi em cortes histológicos incluídos em parafina, uma vez que possibilitaram a clara diferenciação dos esporos de outras estruturas teciduais. Nos tecidos incluídos em resina plástica, as colorações de azul de toluidina-fucsina e azul de toluidina também facilitaram o encontro do agente. Por outro lado, a técnica tricrômica apresentou grande variabilidade nos resultados, sendo, portanto, pouco indicada para o diagnóstico em tecido. As demais técnicas - H-E, calcoflúor, Grocott, Giemsa e PAS - não permitiram a fácil identificação do E. cuniculi.

Técnicas de coloração para detecção de Encephalitozoon cuniculi em cortes histológicos

In this study, it was investigated different staining techniques applied to histological sections for identification of Encephalitozoon cuniculi. It was used liver fragments from Balb-c mice immunosuppressed with cyclophosphamide and inoculated with spores of Encephalitozoon cuniculi. The histological paraffin embedded sections were stained with hematoxylin-eosin (H-E), modified trichrome, Gram-Chromotrope, Giemsa, Brown-Hopps, PAS, Ziehl-Neelsen, and Grocott and also by the technique of calcofluor. Toluidine blue-fuchsin and toluidine blue stainings were used for the cuts embedded in plastic resin. Gram-Chromotrope, Brown-Hopps and Ziehl-Neelsen staining techniques permitted the best visualization of the spores for the diagnosis of E. cuniculi in histological paraffin embedded sections, since they allowed the clear differentiation of the spores among other tissue structures. In tissues embedded in plastic resin, toluidine blue-fuchsin and toluidine blue stainings also facilitate the finding of the agent. On the other hand, the trichrome technique showed great variability on results, therefore, allowing the identification of the parasite in tissue. The other techniques, H-E, calcofluor, Grocott, Giemsa and PAS did not permited the easy identification of the E. cuniculi spores.

No presente trabalho, foram avaliadas diferentes técnicas de coloração aplicadas a cortes histológicos para a identificação de Encephalitozoon cuniculi. Foram utilizados fragmentos hepáticos de camundongos Balb-c, imunossuprimidos com ciclofosfamida e inoculados com esporos de Encephalitozoon cuniculi. Os cortes histológicos incluídos em parafina foram corados pelas técnicas de hematoxilina-eosina (H-E), tricrômica modificada, Gram-Chromotrope, Giemsa, Brown-Hopps, PAS, Ziehl-Neelsen e Grocott, e ainda pela técnica de calcoflúor. As colorações azul de toluidina-fucsina e azul de toluidina foram utilizadas para os cortes incluídos em resina plástica. As técnicas de Gram-Chromotrope, Brown-Hopps e Ziehl-Neelsen foram as que permitiram melhor visualização dos esporos para o diagnóstico de E. cuniculi em cortes histológicos incluídos em parafina, uma vez que possibilitaram a clara diferenciação dos esporos de outras estruturas teciduais. Nos tecidos incluídos em resina plástica, as colorações de azul de toluidina-fucsina e azul de toluidina também facilitaram o encontro do agente. Por outro lado, a técnica tricrômica apresentou grande variabilidade nos resultados, sendo, portanto, pouco indicada para o diagnóstico em tecido. As demais técnicas - H-E, calcoflúor, Grocott, Giemsa e PAS - não permitiram a fácil identificação do E. cuniculi.

Técnicas de coloração para detecção de Encephalitozoon cuniculi em cortes histológicos

In this study, it was investigated different staining techniques applied to histological sections for identification of Encephalitozoon cuniculi. It was used liver fragments from Balb-c mice immunosuppressed with cyclophosphamide and inoculated with spores of Encephalitozoon cuniculi. The histological paraffin embedded sections were stained with hematoxylin-eosin (H-E), modified trichrome, Gram-Chromotrope, Giemsa, Brown-Hopps, PAS, Ziehl-Neelsen, and Grocott and also by the technique of calcofluor. Toluidine blue-fuchsin and toluidine blue stainings were used for the cuts embedded in plastic resin. Gram-Chromotrope, Brown-Hopps and Ziehl-Neelsen staining techniques permitted the best visualization of the spores for the diagnosis of E. cuniculi in histological paraffin embedded sections, since they allowed the clear differentiation of the spores among other tissue structures. In tissues embedded in plastic resin, toluidine blue-fuchsin and toluidine blue stainings also facilitate the finding of the agent. On the other hand, the trichrome technique showed great variability on results, therefore, allowing the identification of the parasite in tissue. The other techniques, H-E, calcofluor, Grocott, Giemsa and PAS did not permited the easy identification of the E. cuniculi spores.

No presente trabalho, foram avaliadas diferentes técnicas de coloração aplicadas a cortes histológicos para a identificação de Encephalitozoon cuniculi. Foram utilizados fragmentos hepáticos de camundongos Balb-c, imunossuprimidos com ciclofosfamida e inoculados com esporos de Encephalitozoon cuniculi. Os cortes histológicos incluídos em parafina foram corados pelas técnicas de hematoxilina-eosina (H-E), tricrômica modificada, Gram-Chromotrope, Giemsa, Brown-Hopps, PAS, Ziehl-Neelsen e Grocott, e ainda pela técnica de calcoflúor. As colorações azul de toluidina-fucsina e azul de toluidina foram utilizadas para os cortes incluídos em resina plástica. As técnicas de Gram-Chromotrope, Brown-Hopps e Ziehl-Neelsen foram as que permitiram melhor visualização dos esporos para o diagnóstico de E. cuniculi em cortes histológicos incluídos em parafina, uma vez que possibilitaram a clara diferenciação dos esporos de outras estruturas teciduais. Nos tecidos incluídos em resina plástica, as colorações de azul de toluidina-fucsina e azul de toluidina também facilitaram o encontro do agente. Por outro lado, a técnica tricrômica apresentou grande variabilidade nos resultados, sendo, portanto, pouco indicada para o diagnóstico em tecido. As demais técnicas - H-E, calcoflúor, Grocott, Giemsa e PAS - não permitiram a fácil identificação do E. cuniculi.