Infecção intratorácica com Paracoccidioides brasiliensis em modelo experimental murino

Abstract

Paracoccidioidomycosis or South American blastomycosis, is a chronic granulomatous human male infection caused by the Paracoccidioides brasiliensis. The present study it considered the standardization of the model of infection with P. brasiliensis for the intrathoracic route in BALB/c mice. This study was monitored by the detection of the P. brasiliensis through the counting of colony forming units and by the presence of DNA of fungi in the lungs of the infected animals in different points (2, 7, 15, 30, 45, 60 and 90 days) and the survival rate of the mice. Moreover, some immune parameters had been evaluated as the nitric oxide production, TNF-alpha, IFN-gamma, and IL-10 for cells in the intrathoracic washed, total and distinguishing counting of cells of the intrathoracic washed, the lung histopathology and the detection of specific antibodies anti-P. brasiliensis in the lungs and serum. The results show a gradual increase of the number of colonies and P. brasiliensis DNA in the lungs. Until 15 day after the infection can be observed an increase in the nitric oxide production and IFN-gamma for the cells of the washed, as well as an increase of the total number of cells and the percentage of mononuclear. From 30 day after the infection observes an increase of specific antibodies (IgG1) in the serum and the lung, an increase of the production of IL-10 and TNF-alpha for the cells of the washed and consequent reduction of the IFN-gamma production and nitric oxide. Moreover, observed an increase of the percentage of cells polimorphonuclear in the washed. In the histopathology it can be evidenced a gradual increase in the size and complexity of granulomas in the cuts. The mice used in the survival study had started to die in 60 day after the infection. The results show an initial reply of the host with a Th1 profile moving during the infection for a Th2 reply that leads to the death of the BALB/c mice.