RESUMO
BACKGROUND: Dialyzable leukocyte extracts (DLEs) contain molecules smaller than 10 kDa with biological activity in receptor organisms. Primarily, they participate in the regulation of the Th1 immune response, which is essential for the control of several intracellular infections, such as toxoplasmosis. This disease is associated with congenital infection, encephalitis or systemic infections in immunocompromised individuals. The clinical course of this infection fundamentally depends on a well-regulated immune response and timely treatment with the appropriate drugs. OBJECTIVE: The aim of this study was to evaluate the effect of treatment with a leukocyte extract, derived from crocodile lymphoid tissue, on the histopathology and brain parasite load in NIH mice that had been infected with cysts of Toxoplasma gondii (ME-49 strain). METHODS: The treatment was applied during the acute and chronic stages of the infection. Histopathological changes were evaluated in the ileum, liver and spleen at one, four and eight weeks after infection and in the brain at week 8. The parasite load was evaluated by counting the cysts of T. gondii found in the brain. FINDINGS: Compared to the control mouse group, the mice infected with T. gondii and under treatment with DLE showed less tissue damage, mainly at the intestinal, splenic and hepatic levels. In addition, a greater percentage of survival was observed, and there was a considerable reduction in the parasite load in the brain. CONCLUSIONS: The results suggest that DLE derived from crocodile is a potential adjunctive therapy in the conventional treatment of toxoplasmosis.
Assuntos
Encéfalo/patologia , Baço/patologia , Toxoplasmose Animal/tratamento farmacológico , Fator de Transferência/uso terapêutico , Jacarés e Crocodilos , Animais , Encéfalo/parasitologia , Modelos Animais de Doenças , Feminino , Tecido Linfoide/química , Camundongos , Carga Parasitária , Distribuição Aleatória , Baço/parasitologia , Toxoplasmose Animal/patologia , Fator de Transferência/isolamento & purificaçãoRESUMO
BACKGROUND Dialyzable leukocyte extracts (DLEs) contain molecules smaller than 10 kDa with biological activity in receptor organisms. Primarily, they participate in the regulation of the Th1 immune response, which is essential for the control of several intracellular infections, such as toxoplasmosis. This disease is associated with congenital infection, encephalitis or systemic infections in immunocompromised individuals. The clinical course of this infection fundamentally depends on a well-regulated immune response and timely treatment with the appropriate drugs. OBJECTIVE The aim of this study was to evaluate the effect of treatment with a leukocyte extract, derived from crocodile lymphoid tissue, on the histopathology and brain parasite load in NIH mice that had been infected with cysts of Toxoplasma gondii (ME-49 strain). METHODS The treatment was applied during the acute and chronic stages of the infection. Histopathological changes were evaluated in the ileum, liver and spleen at one, four and eight weeks after infection and in the brain at week 8. The parasite load was evaluated by counting the cysts of T. gondii found in the brain. FINDINGS Compared to the control mouse group, the mice infected with T. gondii and under treatment with DLE showed less tissue damage, mainly at the intestinal, splenic and hepatic levels. In addition, a greater percentage of survival was observed, and there was a considerable reduction in the parasite load in the brain. CONCLUSIONS The results suggest that DLE derived from crocodile is a potential adjunctive therapy in the conventional treatment of toxoplasmosis.
Assuntos
Animais , Feminino , Camundongos , Encéfalo/parasitologia , Encéfalo/patologia , Toxoplasmose Animal/patologia , Toxoplasmose Animal/tratamento farmacológico , Fator de Transferência/isolamento & purificação , Fator de Transferência/uso terapêutico , Jacarés e Crocodilos , Tecido Linfoide/química , Parasitos , Baço/parasitologia , Modelos Animais de DoençasRESUMO
Thymulin is a well-characterized thymic hormone that exists as a nonapeptide coupled to equimolar amounts of Zn2+. Thymulin is known to have multiple biological roles, including T cell differentiation, immune regulation, and analgesic functions. It has been shown that thymulin is produced by the reticulo-epithelial cells of the thymus, and it circulates in the blood from the moment of birth, maintain its serum level until puberty diminishing thereafter in life. To study the localization of this hormone, we prepared polyclonal and monoclonal antibodies against the commercial peptide and utilized immunocytochemical techniques for visualization. The results indicate that thymulin stains the thymic reticular cells, the outer layers of Hassall's corpuscles and a large round cellular type, which is keratin-negative and does not show affinity for the common leukocyte antigen (CD-45). In mice, this thymulin-positive cell remains in the thymus throughout life and even appears in relatively increased numbers in old involuted thymi. It also appears in thymus-dependent areas of the spleen and lymph nodes, demonstrating that at least one of the thymus cells containing this peptide can be found in peripheral lymphoid tissue.
Assuntos
Fator Tímico Circulante/análise , Timo/química , Hormônios do Timo/análise , Fatores Etários , Animais , Anticorpos Monoclonais/imunologia , Imuno-Histoquímica , Tecido Linfoide/química , Camundongos , Ratos , Ratos Wistar , Fator Tímico Circulante/imunologia , Hormônios do Timo/imunologiaRESUMO
Thymulin is a well-characterized thymic hormone that exists as a nonapeptide coupled to equimolar amounts of Zn2+. Thymulin is known to have multiple biological roles, including T cell differentiation, immune regulation, and analgesic functions. It has been shown that thymulin is produced by the reticulo-epithelial cells of the thymus, and it circulates in the blood from the moment of birth, maintain its serum level until puberty diminishing thereafter in life. To study the localization of this hormone, we prepared polyclonal and monoclonal antibodies against the commercial peptide and utilized immunocytochemical techniques for visualization. The results indicate that thymulin stains the thymic reticular cells, the outer layers of Hassall's corpuscles and a large round cellular type, which is keratin-negative and does not show affinity for the common leukocyte antigen (CD-45). In mice, this thymulin-positive cell remains in the thymus throughout life and even appears in relatively increased numbers in old involuted thymi. It also appears in thymus-dependent areas of the spleen and lymph nodes, demonstrating that at least one of the thymus cells containing this peptide can be found in peripheral lymphoid tissue.
Assuntos
Animais , Camundongos , Ratos , Fator Tímico Circulante/análise , Timo/química , Hormônios do Timo/análise , Fatores Etários , Anticorpos Monoclonais/imunologia , Imuno-Histoquímica , Tecido Linfoide/química , Ratos Wistar , Fator Tímico Circulante/imunologia , Hormônios do Timo/imunologiaRESUMO
The effect of dexamethasone (a synthetic glucocorticoid) on the activity of antioxidant enzymes (superoxide dismutase (SOD), catalase and glutathione peroxidase) of the lymphoid organs (mesenteric lymph nodes (MLN), spleen and thymus) was investigated. For comparison with non-immune tissues, skeletal muscles (soleus and gastrocnemius (GC) were also studied. As an indication of the occurrence of lipid peroxidation, the content of thiobarbituric acid reactant substances (TBARs) was also determined. Dexamethasone treatment decreased the TBARs content of the lymphoid organs and raised it in the GC and soleus muscles. The activity of Cu/Zn-SOD was reduced in all tissues. However, the activity of Mn-SOD was decreased in the MLN and soleus muscle only. The activity of catalase was reduced in the MLN and thymus and raised in the spleen and GC and soleus muscles. The imposed treatment raised the activity of GPX in the MLN, thymus and spleen and reduced it in GC and soleus muscles. These data led us to postulate that the mechanism for the therapeutic effect of glucocorticoids as antiinflammatory and immunosuppressive agents might include modification of antioxidant enzyme activities.
Assuntos
Dexametasona/farmacologia , Glucocorticoides/farmacologia , Tecido Linfoide/enzimologia , Músculo Esquelético/enzimologia , Oxirredutases/metabolismo , Animais , Catalase/metabolismo , Ativação Enzimática/efeitos dos fármacos , Glutationa Peroxidase/metabolismo , Peroxidação de Lipídeos/efeitos dos fármacos , Linfonodos/química , Linfonodos/enzimologia , Tecido Linfoide/química , Masculino , Músculo Esquelético/química , Ratos , Ratos Wistar , Baço/química , Baço/enzimologia , Superóxido Dismutase/metabolismo , Substâncias Reativas com Ácido Tiobarbitúrico/análise , Timo/química , Timo/enzimologiaRESUMO
The composition of the fatty acids in the thymus, spleen and mesenteric lymph nodes was determined in rats fed polyunsaturated (UFC) or saturated (SFC) fatty acid-rich chow during 6 weeks or 14 months. The results indicated that the lipid composition of fatty acids in these tissues was modified by the type of fat given in the diets. Interestingly, the liver did not show any dietary induced change in the composition of fatty acids. The unsaturation index was raised in the lymphoid organs by UFC either after 6 weeks or 14 months. The ageing process itself increased the degree of unsaturation of fatty acids only in the spleen of the 3 groups. A high degree of unsaturation of fatty acids in the tissues may favour the occurrence of lipid peroxidation. It was noteworthy that a linoleic acid-rich diet (UFC) did not change the content of arachidonic acid in the tissues and so would therefore be unlikely to affect eicosanoid synthesis. As shown by previous studies, these fat-rich diets caused marked changes in the key enzyme activities of glucose and glutamine metabolism in the lymphoid organs, by as yet unknown mechanisms. The results reported here suggest that the effect of fat-rich diets on intermediary metabolism does not occur through eicosanoid synthesis and may be a consequence of the lipid peroxidative process or even alterations in the transcription of the enzymes of glycolysis and glutaminolysis.