[Role of neutrophils in acute lung injury induced by Candida sepsis]

To evaluate the role of inflammatory cells in acute lung injury induced by Candida sepsis, we investigated the time course of cell counts in bronchoalveolar lavage (BAL) fluid, the lung wet-to-dry weight (W/D) ratio and the CFU of Candida after a Candida infection. Male BALB/c mice were injected intravenously with 107 CFU of Candida albicans. They were sacrificed by exsanguination 0, 6, 12, 18, and 24 h after infection. The lung W/D ratio was determined in order to assess the severity of pulmonary edema. BAL was performed 3 times with 0.5 ml of sterile saline. The lung W/D ratio increased significantly 24 h after the injection of Candida, and the neutrophil counts in the BAL fluid increased significantly 12, 18, and 24 h after Candida injection. To assess the effect of neutrophils on Candida-induced acute lung injury, we investigated that of neutrocytosis and neutropenia on cell counts in BAL fluid, of the W/D ratio, and of the CFU of Candida in the lung 24 h after infection. We created neutrocytotic mice using G-CSF, and neutropenic mice with cyclophosphamide. Peripheral neutrophil counts decreased significantly in cyclophosphamide-treated mice, and increased significantly in G-CSF-treated mice. The lung W/D ratio increased significantly in cyclophosphamide-treated mice. Neutrophil counts in BAL fluid increased significantly in G-CSF-treated mice, and decreased significantly in cyclophosphamide-treated mice. The CFU of Candida in the lung decreased significantly in G-CSF-treated mice, and increased significantly in cyclophosphamide-treated mice. We concluded that neutrophils play a protective role in Candida albicans-induced acute lung injury.