Ação de Cladosporium cladosporioides (Fresen.) G.A de Vries isolado de ambientes climatizados sobre as vias respiratórias de camundongos

Abstract

Among the main contaminants of the air of acclimatized environment are fungi bioaerosol, which are widely distributed in the atmosphere. Amongst the species found, many are able to trigger allergic manifestations and diseases in human and animals, such as Cladosporium cladosporioides. However, the inflammatory profile of the inflammatory response that these fungi cause, when inhaled by healthy individuals, is not yet totally elucidated. Thus, the aim was to evaluate the action of Cladosporium cladosporioides isolated from acclimatized environments on the airways of healthy mice. The air was collected by impaction with Andersen® linear sampler, using petri dishes containing Agar Sabouraud media, for 10 minutes during hours of movement as recommended by the RE Nº 9 of ANVISA. The dishes were incubated at 28 ºC for the period of five days. After the growth of the colonies, they were cultivated as central colonies and subsequently identified based on macro and microscopic characteristics. After identification, the spores of the studied species were suspended in a saline solution to obtain a concentration of 2x105 conidia/mL. Afterwards, 30 μl of this suspension was administered by intranasal pathway in Swiss mice (18–25g, n = 8) of both sexes for the periods of 1, 3, 5, 10 and 15 days. The control group consisted of animals who received the vehicle only (0,1% of Tween 80 + NaCl 0,9%). After 24h of the last instillation, the animals were euthanized to obtain a Bronchoalveolar Lavage (BAL). All the procedures to which the animals were submitted were approved by the Research Ethics Committee of the Federal University of Alagoas (UFAL) under the protocol n° 009515/2011-87. Animals that received conidia for 1 day and 3 days did not have modifications on the pulmonary parenchyma. Nonetheless, there was a significant increase on the total leukocytes count after the 5th and the 10th day of stimulus with conidia. The differential leukocytes count on the 3rd day of exposure unveiled that the lymphocytes population of the BAL had an increase of 57% when compared to the control. The monocytes of BAL showed a rise of 46% after the fifth day. Still, the neutrophils only were statistically high after the 10th day of exposure to the conidia. Histological sections of the lung stained with HE demonstrated an intense migration of polymorphonuclear cells to the pleural cavity, and when stained by PAS showed the presence of mucus only on the 5th day of analysis. After the 3rd day, the lung tissue had intense conidia and hyphae. These data show that the inhalation of C. cladosporioides conidia in low concentrations, present in acclimatized environments, induces the influx of inflammatory cells to the respiratory tract. Therefore, low concentration of fungi spores can be sufficient to trigger inflammatory reactions in healthy individuals.