FIG 5.

(a) MPO activity in lung tissue of mice after intranasal administration of S. pneumoniae (AMRI-SP1), followed by treatment with levofloxacin or ceftriaxone alone or in combination. MPO activity was analyzed as the index of neutrophil infiltration in the lung tissue. The rate of change in absorbance was measured spectrophotometrically at 405 nm. MPO activity was defined as the concentration of enzyme degrading 1 μmol peroxide/min at 37°C and is expressed as the change in absorbance/min · mg of tissue protein. The results were reproduced in three repeated experiments. The data are expressed as mean ± SD results of 4 mice per group. A P value of <0.05 was considered significant. *, significant difference with respect to infected control group; $, significant difference compared to monotherapy with LVX or CRO. A P value of <0.05 was considered significant for all tests. (b) NO production. The data are expressed as mean ± SD of the results of 4 mice per group. Values are expressed as μg NO released per g of tissue. A P value of <0.05 was considered statistically significant. *, significant difference with respect to infected control group; $, significant difference compared to monotherapy with LVX or CRO. A P value of <0.05 was considered significant for all tests. (c) Lung vascular permeability measurement. Shown is the pulmonary vascular permeability in S. pneumoniae-infected groups (mean ± SD of results from 4 mice). The results were reproduced in three repeated experiments. The data are expressed as mean ± SD. A P value of <0.05 was considered significant. *, significant difference with respect to infected control group; $, significant difference compared to monotherapy with LVX or CRO. A P value of <0.05 was considered significant for all tests.