No abstract

By using a T, B, or NK cell-deficient mouse strain (recombinase-activating gene (RAG)-1−/−/common cytokine receptor γ-chain (γCR)), and T and B cell and IFN-γ-deficient (RAG-1−/−/IFN-γ−/−) mice, we have studied the generation of immunity against infection by Chlamydia pneumoniae. We found that IFN-γ secreted by innate-cell populations protect against C. pneumoniae infection. However, NK cells were not needed for such IFN-γ-dependent innate immune protection. Inoculation of wild type, but not IFN-γ−/− bone marrow-derived macrophages protected RAG-1−/−/IFN-γ−/− mice against C. pneumoniae infection. In line, pulmonary macrophages from RAG-1−/− C. pneumoniae-infected mice expressed IFN-γ mRNA. Reconstitution of RAG-1−/−/γcR−/− or RAG-1−/−/IFN-γ−/− mice with CD4+ or CD8+ cells by i.v. transfer of FACS sorted wild type spleen cells (SC) increased resistance to C. pneumoniae infection. On the contrary, no protection was observed upon transfer of IFN-γ−/− CD4+ or IFN-γ−/− CD8+ SC. T cell-dependent protection against C. pneumoniae was weaker when IFN-γR−/− CD4+ or IFN-γR−/− CD8+ SC were inoculated into RAG-1−/−/IFN-γ−/− mice. Thus both nonlymphoid and T cell-derived IFN-γ can play a central and complementary role in protection against C. pneumoniae. IFN-γ secreted by nonlymphoid cells was not required for T cell-mediated protection against C. pneumoniae; however, IFN-γ regulated T cell protective functions.

The leaves of guaco (Mikania glomerata and M. laevigata) are widely used for the treatment of asthma and bronchitis. An LC method for the quantification of coumarin and O-coumaric acid in medicinal extracts was developed and validated for linearity, limit of detection, accuracy, precision, as well as intra- and inter-day variations. Extracts and isolated markers were tested in the mice allergic pneumonitis model and the histopathological profile of the lung tissue was analysed. The values found for coumarin and O-coumaric acid in a fluid extract were 1.53 and 1.69 mg/mL, respectively, for M. glomerata, and 0.96 and 0.38 mg/mL for M. laevigata. The values found for the lyophilised aqueous extract were 0.22 and 0.11 mg/mL of coumarin and O-coumaric acid in M. glomerata and 0.05 and 0.02 mg/mL in M. laevigata, respectively . The analysed samples from the species M. glomerata presented more coumarin and O-coumaric acid than the analogous M. laevigata species. Both coumarin and O-coumaric acid are part of the phytocomplex which is responsible for the therapeutic activity of the guaco species. The lyophilisation process generated some alterations in the extract, in comparison with the fresh aqueous extract, and these extracts did not present anti-inflammatory activity. Comparing the histopathological images of the groups tested, a haemorrhagic profile of lung tissue of animals treated with lyophilised extract, O-coumaric acid and coumarin is observed, but not for the group treated with hydroalcoholic extract. It is probable that some protective effect of the whole extract (lost during the lyophilisation process) blocks the harmful effects of the isolated markers.

No abstract

The microbicidal activity of macrophages in an inflammatory milieu has been related to the production of a large number of cytokins and intermediary metabolites of oxygen and nitrogen among them, nitric oxide (NO). Considering that granulomatous inflammation is predominantly composed of macrophages and epithelioid cells, we decided to investigate the participation of NO in this peculiar type of inflammation. Two models were used: glass cover slip implantation into the subcutaneous tissue of mice and, the inoculation of live bacillus Calmette-Guérin (BCG) into the footpad of the animals. Using a histochemical method for the detection of NO synthase and of the concentration of citrulin metabolized by cells obtained from cover slips implanted on different time intervals or BCG-activated peritoneal cells, it was possible to demonstrate that epithelioid cells do not produce NO. Cells from granuloma induced by BCG inoculation express NO synthase, with different degrees of reactivity with a higher intensity in the cytoplasm of cells located in the edge of the lesions. The expression of NO synthase in the cytoplasm of these cells decreases with the age of the lesions. It could also be demonstrated that in mice treated with l-name, an inhibitor of NO metabolism, the lesions induced by BCG lost the granulomatous architecture, were necrotic, and had a significant increase in the bacillary load of the lesion. These data allow us to conclude that NO production by macrophages is a determining factor in the organization of the granulomatous lesion and that it also controls the bacterial load in BCG-induced lesions in mice.

Vernonia scorpioides has been widely used in Brazil to treat skin problems and chronic wounds, such as ulcers of the lower limbs and diabetic lesions. In the present study, we investigated the effect of a dichloromethane (DCM) fraction of V. scorpioides leaf extract on Ehrlich ascitic and solid tumor-bearing mice. The animals were treated once a day with the DCM fraction at a concentration of 5 mg/kg, administered ip during and after the development of the tumor. The lifespan, weight, number and type of leukocytes, number of tumor cells, volume of solid and ascitic tumors were measured. The development of the tumor with pre-treated tumor cells in vitro with the DCM fraction (5 mg/kg) was analyzed and the animals were sacrificed after 7 days. The DCM fraction (5 mg/kg) totally inhibited tumor development when in direct contact with tumor cells, and also ascitic tumor development with in vitro treatment or when administered ip, in loco (after 7 days). Animals treated with the DCM fraction increased their lifespan ca. 2 weeks and maintained their body weight for 30 days. When applied immediately after the inoculation of the tumor cells in vivo, it totally abolished tumor development, with tumor development only decreasing when treatment was started 3 days after the tumor challenge. These data suggest an antineoplastic activity of the fraction. Oral or ip administration of DCM fraction (5 mg/kg) for 7 days did not reduce the solid tumor volume. The cytotoxic activity described here differs from the conventional immune suppressing profile of standard chemotherapy because it increases neutrophil influx to the peritoneal cavity. These results show that, besides exhibiting a tumoricidal activity, the DCM fraction also exhibits inflammatory activity.

RESUMO: "Infl uência do óleo essencial de Melaleuca alternifolia na cicatrização de alveolite dental infectada: um estudo histológico em ratos". A planta Melaleuca alternifolia é nativa da Austrália e a destilação de suas folhas produz um óleo essencial conhecido por óleo de Melaleuca, ou Tea tree oil, usado como antimicrobiano. Nesse estudo, foi verifi cado a atividade deste óleo no processo de reparo de alvéolos dentais infectados. 48 ratos foram utilizados (Rattus novergicus albinus, Wistar) e após a extração do dente e posterior infecção do alvéolo com Staphylococcus aureus, os animais foram separados em três grupos: Grupo I: curetagem e irrigação do alvéolo com soro fi siológico; Grupo II: curetagem e irrigação com soro fi siológico e tratamento com Rifocina 25 mg; e Grupo III: curetagem e irrigação com soro fi siológico e aplicação tópica de óleo de Melaleuca 20%. Os animais foram sacrifi cados 24 horas, 7, 14 e 21 dias após o tratamento e o processo de reparo do alvéolo dental foi analisado por microscopia ótica. Os resultados foram submetidos à análise quantitativa e qualitativa e foi possível concluir que o óleo a 20% causou um retardo no processo de reparo dos alvéolos dentais infectados dos ratos, demonstrado por maior área de necrose e menor osteogênese. Unitermos: Melaleuca alternifolia, Staphylococcus aureus, alvéolo dental. ABSTRACT:The plant Melaleuca alternifolia is native to Australia. The distillation of its leaves produces an essential oil, commonly known as oil of Melaleuca, or Tea tree oil, which present antimicrobial activity. This study investigates the action of this oil on the repair process of infected dental alveoli. 48 rats were used (Rattus novergicus albinus, Wistar). After tooth extraction and posterior infection of the dental alveoli with Staphylococcus aureus, the animals were separated into three groups: Group I: curettage and irrigation with physiologic saline solution; Group II: curettage and irrigation with physiologic saline solution and topical application of rifamycin diethylamide B 25 mg; and Group III: curettage and irrigation with physiologic saline solution and topical application of oil of Melaleuca 20%. The animals were sacrifi ced 24 hours, 7, 14 and 21 days after the treatment with powder and the repair process of the dental alveoli was analyzed using an optical microscope. The results were submitted to qualitative and quantitative analysis and it was concluded that tea tree oil at 20% caused a delay in the repair process of infected dental alveoli in rats, as demonstrated by the presence of more necrosis area and less osteogenesis.

No abstract