Figure 6

Bacterial invasion in internal organs. A. Morphological changes in the spleen and liver. Mice were sacrificed at 14 dpi, and the spleen and liver were harvested. Remarkable splenomegaly was observed in mice inoculated with JOL401 via the oral route and with JOL2782 by the IM route. Hepatomegaly was observed with whitish lesions denoted by black arrowheads that were prominent in mice subjected to oral injection of JOL401, and a small lesion was noted in mice intramuscularly inoculated with JOL2782. B. Histopathological analysis. Mice were inoculated with Salmonella strains, and the effect on the organs was investigated and compared with the organ samples of mice receiving PBS as a placebo. Histopathological changes in the spleen, liver, lung, and brain collected at 3 dpi were studied. Prominent tissue dispersion of red pulp in the spleen as an indication of inflammation was observed in mice inoculated with JOL401 in comparison with attenuated strains and is represented by black arrowheads. Mild to moderate infiltration of inflammatory cells was observed in the liver, denoted by black arrowheads. A similar accumulation of macrophages as an indication of inflammation was noted in the lung and brains of JOL401 WT strain-inoculated mice. Images were obtained at 100 × magnification, and inset images were obtained at 400 × magnification. The scale bar indicates 200 μm.